Sub-Atlantic and medio-European forests of Quercus robur and Quercus petraea, with Carpinus betulus, developed on meso-oligotrophic soils, less hydromorphic than those occupied by the often sympatric forests of unit G1.A13, characterized by the replacement of the groups of Primula elatior and Lamium galeobdolon, well represented in the forests of unit G1.A13, by those of Deschampsia flexuosa and of Maianthemum bifolium, transgressives from the Quercion. They constitute the prevalent oak-hornbeam forests of the Münster basin, the Rhenish and Mosan regions, the northwestern Hercynian lands, Lorraine and the eastern Paris basin, Burgundy.