Rive Gauche students, senators, and book editors who dine here are on to a good thing, since this jolly restaurant serves some of the best cuisine régionale in Paris. Owner Bernard Patou and his wife Véronique take a contagious pleasure in serving up the best of their home turf -- the Aude, a long, narrow region in the Languedoc-Roussillon. Almost everyone orders the cassoulet, bubbling hot in a small, high-sided ceramic dish and filled to the brim with white beans, sausage, and preserved duck. What makes it special here is that the meats are grilled separately before being added to the pot, reducing the fat in the finished dish. Of the house wines, go with the rich, cherry-color Corbières. Good-value prix-fixe menus are also available at lunch and dinner. Métro: Odéon.