Fort de Charenton is a fortification built in 1842 in the community of Maisons-Alfort, and part of the Paris defences planned by Adolphe Thiers.After the fall of Napoleon I in 1814, and again after Napoleon's defeat at Waterloo in 1815, Paris was occupied by foreign forces. To counter new invasion and occupation, defensive works were planned. In 1841 a new fortified enclosure of Paris was proposed, becoming known as the Thiers wall after its chief proponent, prime minister Adolphe Thiers.