As is common in Europe, the St Germain des Prés neighborhood is named after its church, in this case the sixth-century Benedictine Église de St-Germain-des-Prés, named after St 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 St 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 St Germain des Prés, at historic Les Deux Magots and Café de Flore.
The M4 has a St 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.