Provisional text

JUDGMENT OF THE COURT (First Chamber)

5 June 2025 ( * )

( Reference for a preliminary ruling – Public procurement – Directives 2004/17/EC and 2004/18/EC – Principle of equal treatment – Obligation of transparency – Public works contract – Applicability by analogy to a public works contract, pursuant to a judicial interpretation, of rules on guarantees in respect of contracts for sale )

In Case C‑82/24,

REQUEST for a preliminary ruling under Article 267 TFEU from the Sąd Okręgowy w Warszawie (Regional Court, Warsaw, Poland), made by decision of 21 December 2023, received at the Court on 1 February 2024, in the proceedings

Miejskie Przedsiębiorstwo Wodociągów i Kanalizacji w m.st. Warszawie S.A.

v

Veolia Water Technologies sp. z o.o.,

Krüger A/S,

OTV France,

Haarslev Industries GmbH,

Warbud S.A.,

THE COURT (First Chamber),

composed of F. Biltgen, President of the Chamber, T. von Danwitz, Vice-President of the Court, acting as Judge of the First Chamber, A. Kumin, I. Ziemele and S. Gervasoni (Rapporteur), Judges,

Advocate General: M. Campos Sánchez-Bordona,

Registrar: A. Calot Escobar,

having regard to the written procedure,

after considering the observations submitted on behalf of:

– Miejskie Przedsiębiorstwo Wodociągów i Kanalizacji w m.st. Warszawie S.A., by P. Celiński and Ł. Matyjas, adwokaci,

– Veolia Water Technologies sp. z o.o., Krüger A/S, OTV France, Haarslev Industries GmbH and Warbud S.A., by A. Bolecki, radca prawny, and S. Drozd, adwokat,

– the Polish Government, by B. Majczyna and D. Lutostańska, acting as Agents,

– the European Commission, by L. Malferrari, M. Owsiany-Hornung and G. Wils, acting as Agents,

after hearing the Opinion of the Advocate General at the sitting on 6 February 2025,

gives the following

Judgment

1 This request for a preliminary ruling concerns the interpretation of Article 2 of Directive 2004/18/EC of the European Parliament and of the Council of 31 March 2004 on the coordination of procedures for the award of public works contracts, public supply contracts and public service contracts (OJ 2004 L 134, p. 114).

2 The request has been made in proceedings between, on the one hand, Miejskie Przedsiębiorstwo Wodociągów i Kanalizacji w m.st. Warszawie S.A. (‘the contracting entity’) and, on the other hand, Veolia Water Technologies sp. z o.o. (‘Veolia’), Krüger A/S, OTV France, Haarslev Industries GmbH and Warbud S.A. (taken together, ‘the consortium of undertakings’) concerning the payment of contractual penalties and compensation for improper performance of a public works contract for the modernisation and extension of the Czajka sewage treatment plant (Poland).

Legal context

European Union law

Directive 2004/17/EC

3 Under Article 4 of Directive 2004/17/EC of the European Parliament and of the Council of 31 March 2004 coordinating the procurement procedures of entities operating in the water, energy, transport and postal services sectors (OJ 2004 L 134, p. 1, headed ‘Water’:

‘1. This Directive shall apply to the following activities:

(a) the provision or operation of fixed networks intended to provide a service to the public in connection with the production, transport or distribution of drinking water; or

(b) the supply of drinking water to such networks.

2. This Directive shall also apply to contracts or design contests awarded or organised by entities which pursue an activity referred to in paragraph 1 and which:

(a) are connected with hydraulic engineering projects, irrigation or land drainage, provided that the volume of water to be used for the supply of drinking water represents more than 20% of the total volume of water made available by such projects or irrigation or drainage installations, or

(b) are connected with the disposal or treatment of sewage.

3. The supply of drinking water to networks which provide a service to the public by a contracting entity other than a contracting authority shall not be considered a relevant activity within the meaning of paragraph 1 where:

(a) the production of drinking water by the entity concerned takes place because its consumption is necessary for carrying out an activity other than those referred to in Articles 3 to 7; and

(b) supply to the public network depends only on the entity’s own consumption and has not exceeded 30% of the entity's total production of drinking water, having regard to the average for the preceding three years, including the current year.’

4 Article 10 of that directive, headed ‘Principles of awarding contracts’, provides:

‘Contracting entities shall treat economic operators equally and non-discriminatorily and shall act in a transparent way.’

5 Article 38 of the same directive, entitled ‘Conditions for performance of contracts’, is worded as follows:

‘Contracting entities may lay down special conditions relating to the performance of a contract, provided that these are compatible with Community law and are indicated in the notice used as a means of calling for competition or in the specifications. The conditions governing the performance of a contract may, in particular, concern social and environmental considerations.’

Directive 2004/18

6 Under Article 2 of Directive 2004/18, headed ‘Principles of awarding contracts’:

‘Contracting authorities shall treat economic operators equally and non-discriminatorily and shall act in a transparent way.’

7 Article 12 of that directive, headed ‘Contracts in the water, energy, transport and postal services sectors’, states:

‘This Directive shall not apply to public contracts which, under Directive [2004/17], are awarded by contracting authorities exercising one or more of the activities referred to in Articles 3 to 7 of that Directive and are awarded for the pursuit of those activities, or to public contracts excluded from the scope of that Directive under Article 5(2) and Articles 19, 26 and 30 thereof.

However, this Directive shall continue to apply to public contracts awarded by contracting authorities carrying out one or more of the activities referred to in Article 6 of Directive [2004/17] and awarded for those activities, in so far as the Member State concerned takes advantage of the option referred to in the second subparagraph of Article 71 thereof to defer its application.’

8 Article 26 of the same directive, headed ‘Conditions for performance of contracts’, is worded as follows:

‘Contracting authorities may lay down special conditions relating to the performance of a contract, provided that these are compatible with Community law and are indicated in the contract notice or in the specifications. The conditions governing the performance of a contract may, in particular, concern social and environmental considerations.’

Polish law

The Civil Code

9 Article 353 1 of the ustawa – Kodeks cywilny (Law on the Civil Code) of 23 April 1964 (Dz. U. No 16, item 93), in the version applicable to the dispute in the main proceedings (‘the Civil Code’), provides:

‘Contracting parties may arrange their legal relationship at their own discretion as long as the substance or purpose of the contract is not contrary to the properties (nature) of the relationship, the law or the rules of social conduct.’

10 Article 581 of the Civil Code, which appears in a title of that code dealing with contracts of sale, states, in paragraph 1 thereof:

‘Where, in the performance of its obligations, the guarantor has provided the beneficiary of the guarantee with an item free from defects in place of a defective item, or has carried out the relevant repairs to the item covered by the guarantee, the guarantee period shall begin again from the moment of delivery of the item free from defects or the return of the repaired item. Where the guarantor has replaced part of the item, this provision shall apply mutatis mutandis to the replaced part.’

The Law on public procurement

11 Under Article 29(1) of the ustawa Prawo zamówień publicznych (Law on public procurement) of 29 January 2004 (Dz. U. of 2007, No 223, item 1655), in the version applicable to the dispute in the main proceedings:

‘The subject matter of the contract shall be described in an unequivocal and exhaustive manner, by means of sufficiently precise and comprehensible terms, taking into account the requirements and circumstances which could affect the preparation of a tender.’

12 Article 36(1)(16) of that law, in the version applicable to the dispute in the main proceedings, provides:

‘The specifications shall at least contain:

…

(16) provisions essential to the parties which will be introduced into the concluded public procurement contract, general terms of the contract or model contract, if the contracting authority requires the economic operator to conclude a public procurement contract with it on those terms’.

The dispute in the main proceedings and the question referred for a preliminary ruling

13 On 1 August 2008, following a public procurement procedure awarded by way of open tender, the contracting entity entered into a contract for the modernisation and extension of the Czajka sewage treatment plant with a consortium of undertakings established in various Member States, the lead of which was Veolia, established in Warsaw (Poland). The contract provided, inter alia, for the construction of a sewage sludge thermal treatment plant, encompassing two recuperators on two independent waste incineration lines. The date for completion of the works, initially set at 30 October 2010, was subsequently postponed to 30 November 2012.

14 That contract included a document entitled ‘Quality Guarantee’ (‘the warranty card’), which stated that the warranty period began to run on the date of issue of the certificate of satisfactory performance of the works, for a period of 36 months, and was to expire no later than 30 April 2015, unless it was not possible to proceed with the final tests and acceptance due to circumstances attributable to the other contracting party.

15 Article 6.1 of the warranty card provided that ‘where this warranty card is silent, the relevant provisions of Polish law, including in particular the Civil Code, shall apply mutatis mutandis ’. No clarification was provided as to whether that reference to Polish law extended to the provisions of the Civil Code relating to guarantees in respect of contracts of sale.

16 On 21 March 2013, the certificate of satisfactory performance of the works was issued.

17 On 26 September 2014, the contracting entity notified the consortium of undertakings of a breakdown concerning one of the two recuperators in question. That recuperator was replaced under the warranty card and the new equipment was put into service on 22 February 2016.

18 On 3 March 2015, the contracting entity notified the consortium of undertakings of a second breakdown, concerning the other recuperator. That recuperator was replaced under the warranty card and the new equipment was put into service on 28 April 2016.

19 On 27 November 2018, the contracting entity notified the consortium of undertakings of a new breakdown, this time concerning both recuperators. The consortium refused to repair or replace that equipment on the ground that, in its view, the warranty period had expired.

20 That dispute gave rise to proceedings before the Sąd Okręgowy w Warszawie (Regional Court, Warsaw, Poland), which is the referring court, concerning, inter alia, the payment by the consortium of undertakings of contractual penalties and compensation.

21 According to the referring court, the relationship between the parties is governed, by analogy, by Article 581(1) of the Civil Code, relating to guarantees in respect of contracts for sale, which provides that the warranty period starts again from the moment of delivery of the item free from defects or from the return of the repaired item, with the result that, on 27 November 2018, the recuperators were still covered by the warranty, the period of which had begun to run again on 22 February and 28 April 2016 respectively. Nevertheless, this question is the subject of debate both in the case-law of the Polish courts and in legal literature.

22 The referring court also states that the consortium of undertakings challenges the application of Article 581(1) of the Civil Code on the ground that that provision concerns only contracts of sale and that it was not agreed at any time that it would govern, by analogy, the warranty in the context of the works contract at issue. According to that consortium of undertakings, the application of that provision would be contrary to the principles of transparency, equal treatment and competition set out in Directive 2004/18 and now reproduced in Directive 2014/24/EU of the European Parliament and of the Council of 26 February 2014 on public procurement and repealing Directive 2004/18/EC (OJ 2014 L 94, p. 65), in that it would amount to imposing on it requirements which are not evident from the tender documents or from the Polish legislation in force, but only from a controversial interpretation of the Civil Code.

23 The referring court is uncertain as to the scope, in that context, of the principles of equal treatment and non-discrimination in the case-law of the Court, and more specifically as to whether the assessments made in the judgment of 2 June 2016, Pizzo (C‑27/15, EU:C:2016:404), should be applied to the guarantees applicable in the context of the works contract at issue in the main proceedings. It points out, in particular, that knowledge of national law makes it possible for the operators concerned to set their prices at a fair level, and notes that the application by analogy of the provisions of the Civil Code governing guarantees in respect of contracts for sale could place economic operators from other Member States at a disadvantage compared with national economic operators.

24 In those circumstances, the Sąd Okręgowy w Warszawie (Regional Court, Warsaw) decided to stay the proceedings and to refer the following question to the Court of Justice for a preliminary ruling:

‘Must the principles of transparency, equal treatment and fair competition referred to in Article 2 of Directive [2004/18] (now Article 18(1) of Directive [2014/2014]) be interpreted as precluding an interpretation of national law that would allow the provisions of a public procurement contract concluded with a consortium consisting of entities from different EU Member States to include an obligation that may indirectly affect the determination of the price contained in the tender submitted by that contractor, which obligation is not expressly provided for in the contract or in the tender documents, but arises from a provision of national law that does not apply directly to that contract, but is applicable by analogy?’

Consideration of the question referred

25 As a preliminary point, it should be noted, as the European Commission has done, that, having regard to the subject matter of the works contract at issue in the main proceedings, which relates to the construction of a sewage sludge thermal treatment plant, there is doubt as to whether the dispute in the main proceedings comes within the scope of Directive 2004/18, to which the request for a preliminary ruling refers, or that of Directive 2004/17.

26 Article 12 of Directive 2004/18 provides that it does not apply ‘to public contracts which, under Directive [2004/17], are awarded by contracting authorities exercising one or more of the activities referred to in Articles 3 to 7 of [the latter] Directive and are awarded for the pursuit of those activities’. Article 4 of Directive 2004/17, for its part, provides, inter alia, that that directive is to apply to contracts relating to the provision or operation of fixed networks intended to provide a service to the public in connection with the production, transport or distribution of drinking water.

27 Although, in the light of the subject matter of the works contract at issue, the dispute in the main proceedings appears to come within the scope of Directive 2004/17, rather than that of Directive 2004/18, it is nevertheless for the referring court to ascertain that in the light of all the characteristics of the contract at issue in the main proceedings and taking account of the activity carried out by the contracting entity.

28 In those circumstances, in order to give a useful answer to the referring court, the question referred must be construed as concerning the interpretation of Article 10 of Directive 2004/17, the wording of which is identical to that of Article 2 of Directive 2004/18.

29 In the light of the foregoing, it must be considered that, by its question, the referring court asks, in essence, whether the principle of equal treatment and the obligation of transparency as referred to in Article 10 of Directive 2004/17 must be interpreted as precluding the application by analogy to a works contract, pursuant to a judicial interpretation, of provisions of national law governing guarantees in respect of contracts for sale, the content of which was not expressly stated either in the tender documents or in that works contract.

30 From the outset, it should be noted that the principle of equal treatment, which is one of the fundamental principles of EU law, requires that comparable situations must not be treated differently and that different situations must not be treated in the same way unless such treatment is objectively justified (judgment of 6 October 2021, Conacee , C‑598/19, EU:C:2021:810, paragraph 36 and the case-law cited).

31 In particular, in the field of EU public procurement law, the principle of equal treatment, which constitutes the basis of the EU rules on procedures for the award of public contracts, means, in particular, that tenderers must be in a position of equality when they formulate their tenders, the aim of which is to promote the development of healthy and effective competition between undertakings taking part in a public procurement procedure (judgment of 6 October 2021, Conacee , C‑598/19, EU:C:2021:810, paragraph 37 and the case-law cited).

32 Thus, that principle requires that all tenderers are afforded equality of opportunity when formulating their tenders, which therefore implies that the tenders of all competitors must be subject to the same conditions (judgments of 29 April 2004, Commission v CAS Succhi di Frutta , C‑496/99 P, EU:C:2004:236 paragraph 110, and of 2 June 2016, Pizzo , C‑27/15, EU:C:2016:404, paragraph 36 and the case-law cited).

33 According to settled case-law, the corollary of that principle is the obligation of transparency, the purpose of which is to ensure that there is no risk of favouritism or arbitrariness on the part of the contracting authority. That obligation means that all the conditions and detailed rules of the award procedure must be drawn up in a clear, precise and unequivocal manner in the contract notice or specifications so that, first, all reasonably informed tenderers exercising ordinary care can assess their exact significance and understand them in the same way, and, second, the contracting authority is able to ascertain whether the tenders submitted satisfy the criteria applying to the relevant contract (see, to that effect, judgments of 29 April 2004, Commission v CAS Succhi di Frutta , C‑496/99 P, EU:C:2004:236, paragraph 111; of 2 June 2016, Pizzo , C‑27/15, EU:C:2016:404, paragraph 36, and of 4 April 2019, Allianz Vorsorgekasse , C‑699/17, EU:C:2019:290, paragraph 62 and the case-law cited).

34 In that respect, it is important to underline that the Court has also held that the principle of equal treatment and the obligation of transparency, which govern all procedures for the award of public contracts, require the substantive and procedural conditions concerning participation in a contract to be clearly defined in advance and made public, in particular the obligations of tenderers, in order that those tenderers may understand exactly the procedural requirements and be sure that the same requirements apply to all candidates (judgment of 2 June 2016, Pizzo , C‑27/15, EU:C:2016:404, paragraph 37 and the case-law cited).

35 Article 10 of Directive 2004/17 sets out those requirements by expressly providing that contracting entities must treat economic operators equally and non-discriminatorily and must act in a transparent way.

36 Although, as is apparent from the very wording of that article, the principle of equal treatment and the obligation of transparency govern the procedure for the award of public contracts, in order to ensure their effectiveness and the attainment of the objectives which they pursue, that principle and that obligation must also be observed by the contracting authority at the stage of performance of the contract concerned.

37 Thus, the Court has already held that the contracting authority is required to comply strictly with the criteria which it has itself laid down not only during the award procedure as such, but, more generally, until the end of the performance phase of the contract in question. It therefore may not alter the general scheme of an invitation to tender by subsequently proceeding unilaterally to amend one of the essential conditions for that invitation to tender, in particular if it is a condition which, had it been included in the contract notice, would have led the tenderers concerned to submit a substantially different tender (see, to that effect, judgment of 29 April 2004, Commission v CAS Succhi di Frutta , C‑496/99 P, EU:C:2004:236, paragraphs 115 and 116).

38 If, when the contract was being performed, the contracting authority could amend at will the very conditions of the invitation to tender, where there was no express authorisation to that effect, the terms governing the award of the contract, as originally laid down, would be distorted (see, to that effect, judgment of 29 April 2004, Commission v CAS Succhi di Frutta , C‑496/99 P, EU:C:2004:236, paragraph 120).

39 A practice of that kind would lead to infringement of the obligation of transparency and the principle of equal treatment of tenderers, since the uniform application of the conditions of the invitation to tender and the objectivity of the procedure would no longer be guaranteed (see, to that effect, judgment of 29 April 2004, Commission v CAS Succhi di Frutta , C‑496/99 P, EU:C:2004:236, paragraph 121).

40 As regards, in particular, the duration of the warranty and the essential conditions for its implementation, it follows from paragraphs 32 to 39 of the present judgment that, in view of their importance for determining the financial conditions of the tenders submitted by the tenderers concerned, it must be held that those elements are among those which must be clearly defined in advance and made public, in order to enable those tenderers to understand exactly the legal and economic conditions to which the award of the contract in question and the detailed rules for its performance are subject, and to ensure that the same requirements apply to all competitors. That is so in particular in the case of works contracts, in which the implementation of the warranty, as is apparent from the facts of the dispute in the main proceedings, may present a significant financial risk for the successful tenderer.

41 Thus, a reasonably well-informed tenderer exercising ordinary care must be able to identify, at the award stage, the events capable, where appropriate, of extending the warranty period and the extent of its obligations in the context of the performance of the contract at issue.

42 It should also be noted that the application of a time limit or essential procedures for implementing a warranty which are not expressly apparent from the documents relating to the public procurement procedure in question or the works contract concerned, but stem from provisions that are not directly applicable to that contract, the content of which is applicable only by analogy, by virtue of an interpretation of national law or a practice of the national authorities, would be particularly disadvantageous for tenderers established in another Member State. Indeed, the level of knowledge of those tenderers, of national law and its interpretation, and of the practice of the national authorities, cannot be presumed to be identical to that of national tenderers (see, to that effect, judgment of 2 June 2016, Pizzo , C‑27/15, EU:C:2016:404, paragraph 46).

43 In the present case, it is apparent from the request for a preliminary ruling that the warranty card contained in the works contract at issue and binding the contracting parties in the main proceedings expressly provided for a warranty period of 36 months, starting from the date of issue of the certificate of satisfactory performance of the works, and referred to the application, mutatis mutandis , of the relevant provisions of Polish law, in particular the Civil Code, for matters not governed by that card.

44 According to the referring court, such a reference would render applicable to the works contract at issue in the main proceedings Article 581(1) of the Civil Code, relating to guarantees in respect of contracts for sale, under which, where the warranty has been implemented within the period initially provided for, ‘the warranty period shall begin again from the moment of delivery of the item free from defects or the return of the repaired item’.

45 As regards the conclusions to be drawn from those factors in the dispute in the main proceedings, it must be borne in mind that, although, in proceedings under Article 267 TFEU, which are based on a clear separation of functions between the national courts and the Court, the national court alone has jurisdiction to find and assess the facts in the case before it and to interpret and apply national law, it is, however, for the Court to provide the national court with such guidance on interpretation that may be necessary for the resolution of the dispute in the main proceedings, while taking account of the information contained in the order for reference as to the national law applicable to that dispute and the facts characterising the latter (see, to that effect, judgment of 21 December 2021, Euro Box Promotion and Others , C‑357/19, C‑379/19, C‑547/19, C‑811/19 and C‑840/19, EU:C:2021:1034, paragraph 134 and the case-law cited).

46 With that in mind, it should be noted that, according to the request for a preliminary ruling, Article 581(1) of the Civil Code appears in a part of that code relating to contracts for sale and it is not apparent from the wording of that provision that its scope extends to works contracts, such as the one at issue in the main proceedings. According to that request, the application, by analogy, of that provision to works contracts is based on a judicial interpretation and is the subject of disagreement between national courts and of debate in legal literature.

47 It must be borne in mind that the Court has stated that Directive 2004/18 does not preclude, in principle, a reference, in the contract notice or contract documents, to legislative or regulatory provisions as regards certain technical specifications where such a reference is, in practice, unavoidable, provided that it is accompanied by all the additional information required by that directive (see, to that effect, judgment of 10 May 2012, Commission v Netherlands , C‑368/10, EU:C:2012:284, paragraph 68 and the case-law cited). In that regard, as the Advocate General observed, in essence, in point 73 of his Opinion, it is the foreseeability related to the operator’s knowledge of national law and the level of legal certainty which that law has to provide to economic operators in the context of public procurement that is decisive.

48 In the light of the factors referred to in paragraph 46 of the present judgment, a reference to national law such as that made by the warranty card does not appear to enable a reasonably well-informed tenderer exercising ordinary care to identify sufficiently clearly, at the tendering stage, that implementation of the warranty within the initial period provided for in the contract concerned is liable to trigger a new guarantee period, nor, a fortiori, does it enable it to identify the obligations which may be incumbent on it in the performance of that contract.

49 It is, however, for the referring court to ascertain whether that is the case by taking into account all the relevant circumstances of the dispute in the main proceedings, and in particular whether the applicability of Article 581(1) of the Civil Code to the contract at issue in the main proceedings was sufficiently clear and foreseeable for the consortium of undertakings, having regard to the fact that Veolia, the lead company of that consortium, was established in Poland.

50 It follows from all of the foregoing that the answer to the question referred is that the principle of equal treatment and the obligation of transparency as referred to in Article 10 of Directive 2004/17 must be interpreted as precluding the application by analogy to a works contract, pursuant to a judicial interpretation, of provisions of national law governing guarantees in respect of contracts for sale, the content of which was not expressly stated either in the tender documents or in the works contract, where the applicability of such provisions is not sufficiently clear and foreseeable to a reasonably informed tenderer exercising ordinary care.

Costs

51 Since these proceedings are, for the parties to the main proceedings, a step in the action pending before the referring court, the decision on costs is a matter for that court. Costs incurred in submitting observations to the Court, other than the costs of those parties, are not recoverable.

On those grounds, the Court (First Chamber) hereby rules:

The principle of equal treatment and the obligation of transparency as referred to in Article 10 of Directive 2004/17/EC of the European Parliament and of the Council of 31 March 2004 coordinating the procurement procedures of entities operating in the water, energy, transport and postal services sectors

must be interpreted as precluding the application by analogy to a works contract, pursuant to a judicial interpretation, of provisions of national law governing guarantees in respect of contracts for sale, the content of which was not expressly stated either in the tender documents or in the works contract, where the applicability of such provisions is not sufficiently clear and foreseeable to a reasonably informed tenderer exercising ordinary care.

[Signatures]

* Language of the case: Polish.