Not Gastronomique, but my favorite place in Paris is Jéroboam at 72 Rue Didot. They have an amazing home-made fois gras as a starter and a brioche de pain perdu for dessert which is just spectacular. I have taken friends from around the world on several occasions, and it has never disappointed.
You might want to try the wine of the former owners as it is very good and very reasonably priced (23 euro a bottle).
I have eaten at some more expensive restaurants in France, but this one is definitely my favorite.
Cheers,
Timo