As is common in Europe, the Saint Germain des Prés neighborhood is named after its church, in this case the sixth-century Benedictine Église de Saint-Germain-des-Prés, named after Saint Germain, in honor of the Bishop of Paris. We have this church to thank for the student-led vibe of the area; they donated the land from the church to the Seine and to the University of Paris, thus creating the Latin Quarter that we know and love today.
The main street in the neighborhood, in the sixth arrondissement, is the Haussmann-designed Boulevard Saint Germain. It has chic stores and plenty of cafes for people watching. In fact, the romance of whiling away the hours at a cafe was practically born in Saint Germain des Prés, at historic Les Deux Magots and Café de Flore.
The M4 has a Saint Germain des Prés stop, which takes you to the southern end of the neighborhood; head north, and the neighborhood ends at the left bank of the Seine.