Poor you! Yup, you can get bad service and bad food in France. But you never leave a tip,good or bad. Under French law the service and taxes are included, no tip is expected and there is no 'service charge' voluntary or otherwise, added to the bill, as is common here. I kept a home in France for 40 years until last year and never tipped in a restaurant nor ever saw a French person do so. You may see a few centimes left from the change, but that's all. Mind, if a tourist does not know the custom, their tip won't be refused!