Article R*49-26 of the French Code of Criminal Procedure
The court is not obliged to refer a priority question of constitutionality challenging, on the same grounds, a legislative provision already before the Cour de cassation or the Conseil constitutionnel. If the question is not referred on this ground, the court shall defer ruling on the merits until it has been informed of the decision of the Cour de cassation or, as the case may be, of the Constitutional Council.