Article 230-47 of the French Code of Criminal Procedure
A technical device may be used, by means of airborne cameras, for the purpose of capturing, fixing, transmitting and recording without their consent the image of one or more persons in a public place, if this operation is required by the necessities: 1° An investigation or enquiry into a crime or misdemeanour punishable by at least three years’ imprisonment; 2° An investigation or enquiry into the causes of death or…