10      In that connection it must be recalled, first of all, that according to settled case-law the subject-matter of an action brought under Article 226 EC is determined by the Commission’s reasoned opinion (see Case C-29/90 Commission v Greece [1992] ECR I-1971, paragraph 12, and Case C-280/89 Commission v Ireland [1992] ECR I-6185, paragraph 7), so that the action must be based on the same grounds and pleas as the reasoned opinion (see Case C-456/03 Commission v Italy [2005] ECR I-5335, paragraph 35 and the case-law cited, and Case C-33/04 Commission v Luxembourg [2005] ECR I-10629, paragraph 36).

7 At the hearing Ireland pointed out that the contested regulations had been revoked on 11 March 1992. However, the Court has consistently held (see judgment of 18 March 1992 in Case C-29/90 Commission v Greece [1992] ECR I-1971, paragraph 12) that the subject-matter of an action brought under Article 169 is determined by the Commission' s reasoned opinion, and even when the default has been remedied after the expiry of the time-limit prescribed by the second paragraph of that article, there is still an interest in pursuing the action in order to establish the basis of liability which a Member State may incur as a result of its default towards other Member States, the Community or private parties.

24 Suffice it to observe that under international law a vessel has the nationality of the State in which it is registered and that it is for that State to determine in the exercise of its sovereign powers the conditions for the grant of such nationality (see judgment of 24 November 1992 in Case C-286/90 Poulsen [1992] ECR I-6019, paragraphs 13, 14 and 15). The contested Irish regulations cannot, therefore, be justified on the basis of public international law.