Is this the real PG throwing around conspiracy theories? Wow.
I'm French and have been living in Paris my whole life. In France you're not allowed to take pictures or movies of people without their consent. If you try to take pictures of strangers in the subway you will be heckled and possibly assaulted, and the police will do nothing to stop it.
I'm not defending my country here -- I'm a photographer and resent this a lot, this attitude is stupid -- but this is how it is.
> No one at an ordinary McDonald's would even notice such a device.
Every fast food and most retail shops now have "private security" who are untrained/uneducated people standing at the door and watching people come and go. I would bet none of them speaks a word of English so it's unlikely the letter from a doctor in the US meant anything to them. They felt entitled to prevent the taking of pictures in the restaurant and felt they were being played with false official documentation.
(Go try and take pictures at any McDonald's in Paris or any other fast food joint and you'll be met with extreme hostility, and possibly physical aggression).
This privatization of security is a very big problem and a scandal in its own right (the rule of law means the state has a monopoly on legitimate violence) and I try hard to never comply with what those security people tell me, and tell them to call the police if they're unhappy -- the fact is that they have absolutely zero legitimate power but since nobody knows it, they have a lot of semblance of power.
But I would be very very surprised if McDonald's in France (on the Champs Élysées!) had restaurants that were a mafia front. Undocumented labor is a more likely possibility, but again, no restaurant or in fact no retail place in Paris will let you take pictures inside their premises without a very strong confrontation. Go ahead and try.