You cannot avoid the historic library of the city of Paris (at 24 rue Pavee, 75004). It is the sanctuary if the collective written memory of Paris.
But for me the essential bookshop is the Librairie Jousseaume (at 45 galerie Vivienne, 75002). Only Mr. Jousseaume himself is able to navigate the maze of this infinite collection of books. It's simple: He has everything, or could have everything.
Other places to find books and book culture in Paris include:
Métro Station: Île de la Cité
Île de la Cité is the ideal place to start: this island sits at the very heart of Paris and is its birthplace; appropriately enough, it has the shape of a cradle. "The head, the heart, the very marrow of Paris," as Gui de Bazoches wrote in the 12th Century.
The Île de la Cité stop consists of a series of wells dug deep into the city's entrails--almost fifty feet (some twenty meters) below the water level of the Seine, and, as in Jules Verne's Voyage to the Center of the Earth, when you go down into it you have the feeling that time moves in reverse. No need of a volcano shaft to get down into the depths, or a Nautilus to dive leagues down below the surface. The Cité stop will do.
Cité's flower market crowds right up to the edge of the subway entrance, and a little further along are the green boxes of the bouquinistes--the vendors of second-hand books and old prints. I can never resist plunging in and always resurface with something, on this occasion two dog-eared histories of Paris.
Métro Station: Saint-Germain-des-Prés
Arriving at the Saint-Germain-des-Prés Métro station, the first things that come to mind are Existentialism, jazz clubs, writers huddled for warmth at tables near the stove-tops of the Deux-Magots, and of course lovers embracing at the Café Flore. These shadows have never entirely vanished from our minds. This is all an illusion, of course, for Jean-Paul Sartre and Simone de Beauvoir, just like Boris Vian, Jacques Prévert, and all the others are long gone. In his or her quest for them, the literary tourist will find only a somewhat pathetic sign stuck on a post at the edge of the sidewalk. "Place Sartre-Beauvoir," it proclaims. The city elders clearly believed it necessary to offer at least a small nod to touristic nostalgia and came up with this dual attribution, posted in a noisy and busy intersection facing the Rue de Rennes and right at the spot where it plunges into Boulevard Saint-German.
The stones of the Romanesque clock tower are more than a thousand years old, and the foundations, still visible in the Saint-Symphorian chapel, date from the same Merovingian period, meaning they go back about 1500 years. The steeple rises up over the neighborhood, somewhat desultorily witness to the sad truth that high-fashion clothing stores have replaced the bookstores to which, not so long ago, students came seeking intellectual nourishment.
Métro Station: Château de Vincennes
When he left the palace inside the walls of Paris, King Charles V had his library installed in one of the towers of the Louvre; his collection of books was the foundation of what would eventually become the Bibliothèque Nationale. Traumatized by the assassination--in his presence--of his two marshals by Étienne Marcel, Charles V refused to spend any more time in the Citè palace, where this terrible event had taken place. Instead he focused on finding a place where his power would be safe, just outside Paris to the Château de Vincennes, a place that is dominated by its dungeon keep, the home and safe-house of kings. This vast assembly of buildings surrounded by beautiful parks--which no longer exist today--afforded greater security than anything within the confines of Paris. But he had to leave his library behind.