All available material of fossil Bibionidae from French Oligocene localities, including the German locality of Kleinkembs right next to the border with France, is revised, and the species redescribed. Several publications (notably Heer 1856, Oustalet 1870 and Théobald 1937) have dealt with this material but there is a large degree of duplication leading to numerous synonyms. In addition, many of the named species have been assigned to the wrong genus. We have found seven species of Penthetria, eleven species of Plecia, seven species of Bibio and a single species of Dilophus in the material of previously named species. Three new species, Penthetria luberonica sp. n., Bibio aquaesextiae sp. n. and Bibiodes provincialis sp. n. are described from French Oligocene localities. The following new combinations are proposed: Penthetria claripennis (Théobald, 1937), Penthetria gigantea (Théobald, 1937), Penthetria graciliventris (Théobald, 1937), Penthetria longiventris (Théobald, 1937), Penthetria nervisinuata (Théobald, 1937), Penthetria subterranea (Théobald, 1937), Plecia morio (Heer, 1849), Bibio major (Oustalet, 1870), Dilophus luteipennis (Théobald, 1937). Many of the species occur from several outcrops, and distinctive faunas can be recognized from Early Oligocene (e.g., Célas and Monteils), Middle Oligocene (e.g., Céreste and Bois d’Asson) and Late Oligocene (e.g. Aix-en-Provence and the German outcrop of Rott). The late Oligocene localities also share some species with the Early Miocene locality of Radoboj, Croatia, but none with the younger locality of Öhningen, Southern Germany. For a number of named species, the type material is poorly preserved and cannot be recognized at the species level, these are commented on and assigned to the lowest taxonomical level to which they can be identified with certainty. The type materials of a number of species appear to be lost; these are placed to genera to the extent that this is possible from the original descriptions and illustrations. Bibio nigripennis Théobald, 1937, nec Brunetti, 1913 is a primary junior homonym and the name must be replaced. The species is moved to the genus Plecia and renamed Plecia theobaldi nom.n.