You can hardly walk along the river Seine and not run into the used and antiquarian book and poster vendors lining the large sections of the banks. Browsing these little stalls is recommended if not for the shopping itself then at least for their unique atmosphere! It is also a great opportunity for souvenir shopping.
Info http://www.frenchmoments.eu/bouquinistes-of-paris/
Address 53 Quai des Grands Augustins, 75006 Paris, France
Coordinates 48°51'19.935" N 2°20'27.403" E