I'm always hesitant about speaking for an entire country, but I'm pretty sure tipping in a restaurant in France would be considered borderline insulting.
I was in Paris recently and all the restaurants that were "tourist-enabled" (e.g, had an English menu) didn't seem at all worried about the tablet credit card machine having a tip option.
Doesn't France have a standardized 15% service charge.
Yes it's included in the prices. Technically it's supposed to go to waiters, but I don't think it really happens. They just get a "livable" flat wage. Back in the days it was customary to just leave the change when paying for your meal in cash, but it was rarely the equivalent of more than a dollar or two.