Yes, it’s the ANSSI, Agence Nationale de la Suritdes Systes d'Information (National Agency of Information System Security), here is the link to report a vulnerability. I strongly recommend that you go through it, in France there is a juridic void on this point, even if I highly doubt that you can go in jail for reporting a vulnerability, someone can still sue you for this. The ANSSI has put this service in place more or less one year ago if I remind well to avoid the problem of people that just report vulnerabilities without harming the company and that get sued for it. You have the needed law’s text on the page I’ve linked, I let you read them.