National Library of France (BNF) contains the royal collections since late Middle Ages. Its activities are spread over seven sites, the main one being the library François Mitterrand site, situated in the 13th district of Paris, on the left bank of the Seine.
It is characterized by four corner towers of 79 meters each corresponding symbolically to four open books:
- Tower of Time
- Tower of Laws
- Tower of Numbers
- Letters of Letters.