Eating out in France : how much does it cost?
In 2015, average rates for a "Menu du jour" seem to be about 15 €. Average prices depend on local factors, including the competitive environment, and the neighbourhood. Many restaurants now offer an alternative and cheaper two-course option, "Entrée + plat" or "Plat + dessert" (starter and main course, or main course and dessert). In many restaurants, the Menu du jour is only available for lunch: in the evening, it is necessary to choose a more expensive menu or choose à la carte. Most respectable restaurants offer a menu of some sort in the region of 20 €. In gourmet restaurants, menus can be quite a bit more expensive.
"Menus" normally include bread, and a carafe of water if requested. They may also include a small carafe of wine. Coffee is normally extra. Check the wine list carefully; restaurants make big mark-ups on the wine, but there are usually house wines avaialble, if you go to the end of the wine list.