You have the right to have a different reading of the Law but all French people rightfully consider that prices in all restaurants and bars include tax and service because that's what French Law requires.

The French law also imposes restaurants and bars to pay their employees at least the minimum wage (SMIC) + benefits (retirement + healthcare).

The 2015 minimum wage in France aka SMIC, (Salaire minimum de croissance) is 9.61 euros per hour, and 1 457,52 euros for workers working 35 hours/week.

Do you really believe that some restaurants and bars could be foolish enough to not reflect this mandatory cost in their prices?

Now, let's go back to the text of the Law.

You are assuming, because the text of the "Arrete du 27 Mars 1987" stipulates "in establishments where service is perceived ........" that there could be "establishments where service is not perceived". .
There are indeed some "other establishments offering food and beverage for on-site consumption", like cafeterias, food courts and concessions where service is not perceived, and it is for this category of businesses that the Law left the door open.

At the end of the day, if you want to leave 15% or 20% of the check to your waiter when the check he gives you mentions "service non compris", that's perfectly fine with me, but personally, I don't.

Respectfully.