The Court of Justice has ruled several times on this issue. As regards the 1995 enlargement (of Austria, Sweden, and Finland), the Court was asked whether it had jurisdiction to rule on acts which occurred in Sweden before that State acceded to the EU, and also whether Sweden was bound by EC law when the relevant acts occurred (Case C-321/97 Andersson  ECR I-3551). The Court ruled as follows:
31. The jurisdiction of the Court of Justice covers the interpretation of Community law
, of which the EEA Agreement forms an integral part, as regards its application in the new Member States with effect from the date of their accession
32. In this case, the Court has been asked to rule directly on the effects of the EEA Agreement
, within the national legal system of which the referring court forms part, during the period prior to accession
33. Accordingly, the Court has no jurisdiction to reply to the first question
This case was followed, as regards Austria, by Case C-300/01 Salzmann  ECR I-4899, in which the Court of Justice ruled that it did not have jurisdiction to answer the questions relating to the application of EC law in Austria before
membership of the EU.
Subsequently, following the enlargement of the EU in 2004 to include a further ten Member States, including the Czech Republic, a Hungarian court similarly asked the Court of Justice about the interpretation of an EC Directive as regards acts which occurred before that Member State joined the EU (Case C-302/04 Ynos  ECR I-371).
The Court of Justice replied as follows:
34 According to the order for reference, by its first and second questions the Szombathelyi Városi Bíróság is seeking an interpretation by the Court of Article 6(1) of the Directive for the purposes of assessing the scope of rules of
35 It must, however, be pointed out that the order for reference states that the facts in the main proceedings occurred before the Republic of Hungary acceded to the European Union.
36 The Court has jurisdiction to interpret the Directive only as regards its application in a new Member State with effect from the date of that State’s accession to the European Union
(see, to that effect, Case C-321/97 Andersson and Wåkerås-Andersson  ECR I-3551, paragraph 31).
37 In this case, as the facts of the dispute in the main proceedings occurred prior to the accession of the Republic of Hungary to the European Union, the Court does not have jurisdiction to interpret the Directive
38 In the light of the foregoing, the answer to the third question referred for a preliminary ruling must be that, in circumstances such as those of the dispute in the main proceedings, the facts of which occurred prior to the accession of
a State to the European Union, the Court does not have jurisdiction
to answer the first and second questions.