General Principles
EU law primacy
EU law takes precedence over the law of the Member States and requires all Member State bodies to give full effect to the various provisions of EU law. National courts are, therefore, required to interpret their national law, to the greatest extent possible, in conformity with the requirements of EU law. This may even result into the change of established case-law, where necessary, if it is based on an interpretation of domestic law that is incompatible with the objectives of a directive (Case C-441/14 DI, para 33).
Where it is unable to interpret national law in compliance with the requirements of EU law, a national court may be required to disapply case-law which represents an obstacle to the full application of EU law, and even any provision of national law which is contrary to a provision of EU law with direct effect (Case C-573/17 Poplawski, para 58, 61). It is not necessary for the parties to expressly plead before the national courts which individual provisions of national law those courts should disapply or interpret in accordance with EU law. Instead, the identification of those provisions and the development of the approach for eliminating any contradiction between national law and EU law is part of the obligation of national courts to achieve the result envisaged by the directive (Opinion in Case C-254/19 Friends of the Irish Environment, para. 67, 69). In that way, the principle of primacy of EU law has made it possible to overcome numerous procedural obstacles arising from national law, in proceedings based on EU law. In some cases, it has led to the national court applying procedural rules and adopting measures in situations not provided for by national law (Case C-415/11 Aziz, para. 64).
However, there are exceptions to the obligation to disapply the conflicting measures if there is an overriding consideration: A risk that the annulment of the measure could create a legal vacuum that is incompatible with that Member State's obligation to adopt measures to transpose another act of EU law concerning the protection of the environment (Case C-41/11 Inter-Environnement Wallonie and Terre wallonne) or another general interest. In any event, any possible the maintenance of the effects of those acts may last only as long as is strictly necessary to remedy the breach found (Case C-24/19 A and Others () and à Nevele).