Lex Deux Magots is a great cafe to eat, drink and people watch. Located in St. German des Pres, it is an ideal location and of course a bit of a tourist trap. Hemingway, Sartre, Picasso used to love hanging out here, hence the historical popularity of the cafe.
Ham, Cheese and Bechamel Sauce. Tasty but definately a tourist trap. Not the best croque monsieur I have ever had but you cannot really go wrong with ham and cheese.