"maison du livre" It is boulevard de malsherbe
Nearest station is St Augustin
here is there web page
http://www.livre-aviation.com/Only recent book but a lot of them
the mussee de l'air have a nice bookshoop
La Machine Volante. 75 rue Claude Decaen paris
12eme station Daumenisle (open the afternoon only wednesday to saturday ) Great place and great price
Librairie Le CARRÉRÈS 21 rue Mayet station Duroc great place for old book but the owner is (not that welcoming) (the price are high)
the small shop (open air shops) on the bank of the seine are a great place to find old book but you need to look as the guy have no idea what he is seeling
if you are there a saturday or a sunday a great place is the second hand book market station porte de vanves (there too you may find or not)