The Archives nationales (French for "National Archives") preserve the national archives of the French state, apart from the archives of the Ministry of Defence and the Ministry of Foreign Affairs, as these two ministries have their own archive services, the Service historique de la défense and the Archives diplomatiques respectively. The Archives nationales have one of the largest and most important archival collections in the world, a testimony to the very ancient nature of the French state which has been in existence for more than eleven centuries already.
The Archives nationales were created at the time of the French Revolution in 1790, but it was a state decree of 1794 that made it mandatory to centralize all the pre-French Revolution private and public archives seized by the revolutionaries, completed by a law passed in 1796 which created departmental archives (archives départementales) in the départements of France to alleviate the burden on the Archives nationales in Paris, thus creating the collections of the Archives nationales as we know them today. In 1800 the Archives nationales became an autonomous body of the French state. Today, they contain about 406 km. (252miles) of documents (the total length of occupied shelves put next to each other), an enormous mass of documents growing every year. The original documents stored by the Archives nationales range from AD 625 to the present.
More information on the Wikipedia page .
The website (in French) is