The Monnaie de Paris was founded in 864 AD. Operating in two sites, one in Pessac in southwest France and the other this building in Paris, it is the oldest continuously operating mint in the world. It houses the very high tech, high security facilities for producing the French Euros today.
The current Hôtel de la Monnaie (which is open to the public) was designed by Jacques-Denis Antoine and finished in 1775. It is a key example of pre-Revolutionary Neoclassicism in Paris.