The OP didn't have a problem understanding the concept of service charge being included IN the price of a meal.

The problem was that this specific establishment was trying to scam those are used to leaving a tip by making it seem normal to leave that 15% (or more).

Informed visitors should feel free to leave whatever they want (or nothing) and not be criticized (by Nationality) for either choice...but the key word is "informed" and this does not refer to a menu statement.

So we should keep reporting such establishments but the thread could be shortened by a cut and paste statement saying:

"There is no requirement to add any additional fee, tip, service charge to ANY establishment on the French side. A small addition will be appreciated but is not required."