THIS LITTLE BISTRO is situated in one of the streets that run alongside the Palais-Royal; where Jean Cocteau has his Paris flat, and where Colette, the celebrated author, used to live. You enter the Caveau Montpensier from the pavement level and descend a few steps to the cellar bistro. Here you will be received by Madame Branet-Monnet, whose establishment has become well-known among tourists, especially Scandinavians, for the quality of its inexpensive food. There are two low-ceilinged comfortable little rooms, with banquettes, where you are attentively served by La Patronne and two trim waitresses. Lanterns and hanging, green plants decorate the red brick walls. French, English, Italian and Spanish are spoken.