Commission made a decision that aid granted (but not yet paid) to an Italian company (L) by the government was in breach of common market and therefore contrary to community law. However Italian courts gave judgment for L and so Italian govt had to pay money over and did so, becoming res judicata in Italian law. Italian govt then tried to claim the money back from L. ECJ held that res judicata law does not apply where it would frustrate the application of community law. National courts must give full effect to provisions of Community law and – if necessary – refuse, of their own motion, to apply any provision of national law that is contrary to those provisions of Community law.