If you're pining for English-language books, Village Voice on rue Princesse in St-Germain-des-Prés is outstanding, but try, too, Brentano's at 37 avenue de l'Opéra, or W. H. Smith at 248 rue de Rivoli.
Visit Village Voice in St-Germain-des-Pres, Brentano's at 37 avenue de l'Opera, or W.H. Smith at 248 rue de Rivoli for English-language books