My policy and simple way I deal with it.

French side - Wait staff is paid a living wage, any tip is optional to me which 99% plus of the time I add a tip but rarely American sized.

Dutch side - I look at the bill. Anything over the amount of what I am paying for the food that is listed on the menu counts towards the tip. I completely understand why a business on the Dutch side would add a line item for tip/service as they have a mix of people from countries that do not tip by custom and people from countries that do. Key item in this - As long as they are honest and upfront with the way they do it.

Cheers!