The Folie St. James was a French landscape garden created between 1777 and 1780 in the Paris suburb of Neuilly-sur-Seine by Claude Baudard de Saint James.
The main attraction of the garden was a collection of forty-eight fabriques, or architectural constructions, placed on both sides of the avenue de Longchamp, and connected by two tunnels. The garden also featured a winding stream, crossed by numerous bridges. The fabriques included kiosques, a Chinese pavilion used an icehouse, temples, a thatched cottage, and an enormous artificial rock formation created of blocks of stone carried in carts from the Forest of Fontainebleau. The rock formation was forty three metres long, eighteen metres wide, and twelve metres high. The portico of a Doric temple was placed in an alcove of the rocks, and two staircases led up to view platforms on top of the rocks. Behind the rocks was a cascade of water which flowed into the stream. Inside the artificial rock hill was a winding tunnel encrusted with minerals and crystals, and several grottoes, as well as a bathing room with a vaulted ceiling and divans.