While I agree that calling the police might curb this guy's activities, there's a reason he's been getting away with it for years. If you're a foreign visitor with a schedule to keep and this clown shows up, do you really want to cancel the rest of your sessions and spend your time at the police station trying to explain this? Forget prostitution, try assault. He's got emails where you agreed to wrestle him and maybe more. Was there mention of a beat down? He claims he paid you and you got carried away doing what he asked. He was just trying to defend himself. It won't look good to people who aren't involved in this world. Lets say that best case they do arrest him without arresting you as well. Are you going to return to France for the trial? What do you think the odds are that a jury of average people are going to listen to both sides and will be confident enough to convict? Sorry, I know I'm describing this in terms of the American justice system, but it still comes down to he said, she said, and somebody who thinks both parties are deviants judging. I agree he's got a pattern, but I don't know how difficult it would be to establish given that the witnesses aren't in the country.
It's not as satisfying as our fantasies, but a good course of action might be to send an email to every woman advertising travel to France and nearby countries (Is it just France? They have a great train system in Europe.) with his pictures and all the information that's been compiled explicitly warning them. Explain to them that he gets off on a free beating, and they shouldn't let him in the room. If he hangs around in the hall, call hotel security or the police to chase him away. Of course that also comes with some risk that you'll miss a day's appointments defending yourself against whatever story he tells about you, but it's a lot better than the stories he could tell if you let him in and his scrotum has swollen to the size of a soccer ball. He obviously wants personal interaction, even if it means he takes a beating - deny it to him.
It makes me think if there's some way women can't screen people so they don't know your room number. Every once in a while I've had a woman meet me in the lobby, but that seems to be because the elevators need a room card. That might not be a bad practice in France. What's he going to do? Jump on you in front of a roomful of people? If he doesn't leave, report him at the desk.