Bois de Vincennes
The Bois de Vincennes, as the Bois de Boulogne, is generally not counted as part of Paris proper, since it consists only of public land without population except for a few custodians. However, for administrative purposes, it is part of the 12ème arrondissement of Paris.
The Bois de Boulogne was officially annexed by the city of Paris in 1929, and was incorporated into the 12ème arrondissement.
In the Bois de Vincennes stands the Château de Vincennes which used to be a favorite second home for many 14th-century kings. Now it is in renovation but it is still open to the public.