I have eaten in French restaurants all over the world, and I can say, with a degree of firmness, that Le Lapin Troubadour in Paris, located in Montmartre, is the absolute best French restaurant in existence. Sure, some other restaurants might be more adventuresome in terms of presentation or ingredients or techniques, however, Le Lapin Troubadour offers balance which is not found anywhere else.
It is a tad difficult to find, however, one you are there, you will enjoy food that is out of this world. French waiters are known to be stand-offish (I wanted to say something else, but I am a polite individual), however, at Le Lapin Troubadour the staff actually seems to enjoy doing what they are doing.
Do not miss the Trebliet du Jour, an invention of the chef. It is actually a pastry, with various fillings and sauces. I hate to repeat myself, however, it is out of this world.