The Costanzo obligation

Abstract

National administrative authorities are obliged to leave provisions of national law unapplied when these are incompatible with EU law. Irrespective of their position and powers under national law, national administrative authorities are supposed to comply with this so-called ‘Costanzo obligation’ as established by the Court of Justice. This raises questions of both European Union law and national constitutional law, particularly with regard to the principle of legality. This book explores three issues. Which European obligations apply to national administrative authorities with regard to provisions of national law that are incompatible with directly effective provisions of European law? Which national constitutional obstacles do they come across by giving effect to these obligations? And how should the tensions between the European obligations and the national constitutional obstacles be solved? The national law part of the research is focused on the legal systems of France, Germany and the Netherlands. The last question combines the European and national perspective and reveals a clash, which gives rise to the question whether the obligation in the current form should be maintained.