Fontainebleau et du Gâtinais is a biosphere reserve located in the Ile de France region, some 70 km south-east of Paris, first designated in 1998 and extended in 2010. The biosphere reserve is composed of temperate deciduous forest, heathlands, open rock areas and several wetlands. In total, the reserve protects 150,544 hectares. The center of the biosphere, is located at 48°22′N 2°33′E.
The biosphere reserve contains two habitats of community interest listed in the European Union’s Habitats, Flora and Fauna Directive: Northern Atlantic wet heaths with Erica tetralix, and forests of slopes, screes and ravines. These are included in the 20 core areas of 3,874 hectares. The core and the buffer zones correspond to the administrative unit of the Forest of Fontainebleau, managed by the Office National des Forêts. The transition area lies essentially in the Parc naturel régional du Gâtinais français but also includes villages and towns with a total of 60,000 inhabitants, including the town of Fontainebleau.
The biosphere reserve encompasses forest lies upon an ancient marine sand-bank which is occasionally overlaid by sandstone.