This article is a short overview of the supremacy of the general principles of law in the case law of the European Court of Justice with special emphasis to the Kucukdeveci case that deals with the protection of the fundamental rights and constitutionalisation of general principles of law. Article will analyse the constitutional changes in France and priority questions on constitutionality. Further analysis will cover joined cases Aziz Melki and Selim Abdeli and the European Court of Justice answer in the question of consistency of the priority questions on constitutionality mechanism with EU law. Finally, author will try to answer the question: is EU law in practice and today's reality supreme to the national law? PUBLICATION ABSTRACT