Around the Rue de La Huchette, you will find several small bars, all good for a cheap drink and laugh with students. Another great place to grab a drink is a tiny bar called Caveau des Oubliettes (TimeOut Paris review here), on the beaten path but often overlooked by tourists. This bar offers strong drinks and live jazz nightly and a bit of history, as the basement here was where prisoners were historically held before their executions.
For more sophisticated dining, Le Coupe Chou on rue Lanneau, was started by three famous French actors Francis Lemonnier, Francis Nani and Christian Azzopardi in the 1960s, and the restaurant/bar quickly became a place where French and foreign performers and stars could intermingle with spectators. Le Coupe Chou has expanded into several neighboring townhouses over the years and time has been taken to restore it to its original 17th century appearance. Lena et Mimile on rue Tournefort is an old-fashioned bistro on a mini-square, and La Perraudin in rue Saint-Jacques still uses red-and-white checkered tablecloths (with old-time prices to match).
Brasserie Balzar, where Camus and Sartre often lunched together, offers not only an excellent menu, but great people-watching property on the rue des Ecoles. The Place St Michel, was once the spot of numerous protests and social uprisings, strikes as well as more light spirited congregations of artists, writers, poets, musicians and dancers. The Boulevard St Michel leads to the Place St Andre, which is lined with bistros and restaurants.
Raclette is a must, and the Saveur de Savoie at 20 rue Saint Severin is about as authentic as the experience gets: a half circle of cheese, melted before your eyes, which you scrape off and pour onto mini plates of potatoes, meats and veggies.
Eric Kayser boulangerie in 14 rue Monge is one of the best bakeries in Paris, and the perfect place to grab breakfast for the next morning. Of course, for any homesick Americans, the authentic Breakfast in America diner offers pancakes, bacon, even huevos rancheros, though if you are looking for the best Mexican food, then the Latin Quarter is predictably the right spot for Anahuacalli at 30 rue des Bernadins that is always packed, so make sure to reserve a spot.