38 If such a
measure or interpretation should, however, prove not to be possible,
attention should be drawn to the importance, both in the legal order of
the European Union and in national legal systems, of the principle of res judicata.
In order to ensure stability of the law and legal relations, as well as
the sound administration of justice, it is important that judicial
decisions which have become definitive after all rights of appeal have
been exhausted or after expiry of the time-limits provided for in that
regard can no longer be called into question (see judgments in Fallimento Olimpiclub, C-2/08, EU:C:2009:506, paragraph 22, and Târșia, C-69/14, EU:C:2015:662, paragraph 28).
EU law does not always require a national court to disapply domestic
rules of procedure conferring finality on a judgment, even if to do so
would make it possible to remedy a breach of EU law by the decision at
issue (see judgments in Kapferer, C-234/04, EU:C:2006:178, paragraph 22, Fallimento Olimpiclub, C-2/08, C:2009:506, paragraph 23, Commission v Slovak Republic, C-507/08, EU:C:2010:802, paragraph 60, Impresa Pizzarotti, C-213/13, EU:C:2014:2067, paragraph 59, and Târșia, C-69/14, EU:C:2015:662, paragraph 29).
40 In the absence of EU legislation in this area, the rules implementing the principle of res judicata
are a matter for the national legal order, in accordance with the
principle of the procedural autonomy of the Member States. However, such
procedural rules must not be less favourable than those governing
similar domestic situations (principle of equivalence) and must not be
framed in such a way as to make it in practice impossible or excessively
difficult to exercise the rights conferred by EU law (principle of
effectiveness) (see judgments in Fallimento Olimpiclub, C-2/08, EU:C:2009:506, paragraph 24, and Impresa Pizzarotti, C-213/13, EU:C:2014:2067, paragraph 54 and the case-law cited).
regards application of the principle of effectiveness, the Court has
held that every case in which the question arises as to whether a
national procedural provision makes the application of EU law impossible
or excessively difficult must be analysed by reference to the role of
that provision in the procedure, its conduct and its special features,
viewed as a whole, before the various national bodies. In that context,
it is necessary to take into consideration, where relevant, the
principles which lie at the basis of the national legal system, such as
the protection of the rights of the defence, the principle of legal
certainty and the proper conduct of the proceedings (see, to that
effect, judgments in Fallimento Olimpiclub, C-2/08, EU:C:2009:506, paragraph 27, and Târșia, C-69/14, EU:C:2015:662, paragraphs 36 and 37 and the case-law cited).
that regard, it must be noted that an interpretation of national law ... can have
the consequence, in particular, that effects are attributed to the
decision of a national court ... which frustrate the application of
EU law, in that they make it impossible for the national courts to
satisfy their obligation to ensure compliance with the third sentence of
Article 108(3) TFEU.
follows therefrom that both the State authorities and the recipients of
State aid would be able to circumvent the prohibition laid down in the
third sentence of Article 108(3) TFEU by obtaining, without relying on
EU law on State aid, a declaratory judgment whose effect would enable
them, definitively, to continue to implement the aid in question over a
number of years. Thus, in a case such as that at issue in the main
proceedings, a breach of EU law would recur ... without it being possible to remedy it.
such an interpretation of national law is likely to deprive of any
useful effect the exclusive power of the Commission ... to assess, subject to review by
the EU Courts, the compatibility of aid measures with the internal
market. If the Commission, to which the Federal Republic of Germany has
in the meantime notified the aid measure constituted by the contracts at
issue, should conclude that it is incompatible with the internal market
and order its recovery, execution of its decision must fail if a
decision of the national court could be raised against it declaring the
contracts forming that aid to be 'in force' (C-505/14, paras 38-44, emphasis added).