Since 1 March 2010, it is possible to contest the constitutionality of a law before any French court (“Priority Preliminary rulings on the issue of constitutionality“).
This possibility is open to individuals and companies in all matters and at any point in time in a court procedure. However, the court itself is not allowed to raise the issue of constitutionality.
Once the issue is brought up before the court, the judge must immediately refer it to the highest courts in private and administrative law (respectively the Cour de cassation and Conseil d’Etat).
These higher Courts must then assess the validity of the request and take their decision within three months. If the request is regarded as founded, the case is sent before the French Constitutional Council (Conseil Constitutionnel).
The Constitutional Council must in particular inform the French President, the Prime Minister and has a three month period in order to reject the request or to decide that the law does not respect the French constitution. In the latter situation, the Constitutional Council will repeal the law in question. During this period during which the issue of constitutionality is being raised before the different courts, the initial procedure is suspended.