71      Such findings do not, however, alter the fact that the system of own resources established pursuant to the Treaty is designed, as regards VAT resources, to create an obligation on the part of the Member States to make available to the Community as own resources a proportion of the amounts which they collect as VAT (see, to that effect, Case C‑30/89 Commission v France [1990] ECR I‑691, paragraph 23). Nor do those findings alter the fact that the Member States are required – for the purposes of ensuring an effective levy of that VAT revenue and of being able, to the extent required by Decisions 2000/597 or 2007/436 and Regulation No 1553/89, to make the corresponding VAT resources available to the Community budget – to respect the various rules of Community law relating to that levy, such as those contained in the Sixth VAT Directive and the VAT Directive, and indeed Regulation No 1798/2003. The situation is, in that regard, appreciably different from that of own resources based on the GNI of the Member States.

60     It follows that that part of the transaction cannot be regarded as having been carried out in the territory of the country within the meaning of Article 2(1) of the Sixth Directive. The same is true, a fortiori, of that part of the transaction which is carried out at sea, a zone which, pursuant to Article 89 of the Convention on the Law of the Sea, is outside the sovereignty of any State (see also, in the area of supply of transport services, Case C‑30/89 Commission v France [1990] ECR I‑691, paragraph 17).

25     In that connection, it must be recalled that, as regards the taxation of services on board ships, the Court has already acknowledged that the Sixth Directive does not prohibit Member States from extending the scope of their tax legislation beyond their territorial limits, so long as they do not encroach on the jurisdiction of other States (Case 283/84 Trans Tirreno Express [1986] ECR 231, and Case C‑30/89 Commission v France [1990] ECR I-691, paragraph 18). Such considerations also apply in relation to taxation of supplies of goods.

14 That specific attachment rule for transport services, which constitutes a derogation from the general rules laid down in Article 9(1) of the Sixth Directive for determining the place where a service is supplied, is thus intended to ensure that each Member State taxes transport services in respect of the parts of the journey completed in its territory (Case C-30/89 Commission v France [1990] ECR I-691, paragraph 16, and C-331/94 Commission v Greece [1996] ECR I-2675, paragraph 10).

10 The Court has previously held that the specific connection rule for transport services laid down in Article 9(2)(b) of the Sixth Directive is intended to ensure that each Member State taxes transport services as regards the parts of the journey carried out in its territory (Case C-30/89 Commission v France [1990] ECR I-691, paragraph 16). That article therefore requires Member States to charge VAT on services supplied by operators organizing round trips by sea as regards the part of the journey within territorial waters. That is, moreover, recognized by the Hellenic Republic itself.