Well, if my experience can help muddy the waters any...

When we were eating out in the Latin Quarter in Paris, the menu and receipt did say "service non compris". I asked the owner if that meant I should leave a 15%ish tip, and he said, absolutely not, as he was paying higher than minimum wage, so the waitstaff was getting their comp from enhanced salary vs service charge. When I asked about my usual 5%, he said that would be just fine. He also added that his staff preferred it that way.

Of course, this could apply only to his place, but that sure confused the heck out of me on how to tip going forward.