Under Article 267 TFEU, courts of the Member States can seek the assistance of the Court of Justice in Luxembourg to help them interpret Union law. When they consider an act of the EU’s Institutions to be illegal, they have no choice but to refer to the ECJ: only the ECJ may conclude to such invalidity. In Case C-368/12 Adiamix, the Court reminds national judges of their duty under such referrals. They must provide the Court with the core factual and legal elements (in national law) relevant for the ECJ to appreciate the context of the referral. They must also furnish the Court with at least their core considerations as to why the EU act at issue might be illegal. In the case at issue, a Commission order to France to recover illegally paid State Aid, led to Adiamix being pursued for repayment in the French courts. Failure of the courts in Nantes to flag the suspicions of illegality, led to inadmissibility of the preliminary review.
Simply passing the buck therefore does not suffice: the national court has to add some core whistles and bells of EU law analysis.