How are they going to force people to accept or to deny something? Now, I think the French government can make a lot of money if they introduce a bill that fine people who believe that 9/11 is the work of US government...
Can't you just picture this scenario:
A very Inspector Clouseau-esque Frencch police officer pulls you over for reckless driving, and right after he asks to see your driver's license, he asks you, "Do you deny the Armenian genocide was committed by the Ottoman Turks?"