The Boulevard Saint-Germain (bulvaʁ sɛ̃ ʒɛʁmɛ̃) is a major street in Paris on the Left Bank (south side) of the Seine River. It curves in a 3.5 kilometer arc from the Pont de Sully in the east (the bridge at the edge of the Île Saint-Louis) to the Pont de la Concorde (the bridge to the Place De La Concorde) in the west and traverses the 5th, 6th, and 7th arrondissements. At its midpoint, the Boulevard Saint-Germain is traversed by the north-south Boulevard Saint-Michel. The boulevard is most famous for crossing the Saint-Germain-des-Prés quarter from which it derives its name.
Vestiges of Former Streets:
Some vestiges of the streets removed to make way for the Boulevard still remain today. There are still a few sections of original streets, e.g., the current rue Gozlin, part of the former rue Sainte-Marguerite, which now consists of a single very short city block between the Place du Quebec (at the Rue Bonaparte) and the rue des Ciseaux.
As well, parts of original streets have more or less been maintained in their original state, but incorporated into the Boulevard as short narrow sections separated from the main Boulevard by a traffic island. For example, there is the South side of the Boulevard at the Place Henri Mondor, South of the Odeon Metro station, which is the former rue des Cordeliers (later renamed rue de l'Ecole de Médecine) and an extension of the current rue de L'Ecole de Médecine, but is now considered as being the Boulevard Saint-Germain.
Another example is the South side of the Boulevard just East of the rue des Ciseaux, which extends the current rue Gozlin, formerly rue Sainte-Marguerite. The North side of the rue Gozlin and this short section extending it represent exactly how much further South the Abbey extended before the creation of the Boulevard Saint-Germain.