The present invention relates to a flap valve (14) for an air extractor (10), in particular of a motor vehicle. The flap valve comprises a rigid or semi-rigid wall (42) and articulation means (40) to allow a pivoting of the flap about an axis (A) substantially parallel to the wall, wherein the articulation means are located on a single edge (44) of the wall. The articulation means are spaced from the wall and comprise a swivel element (40). The swivel elements are preferably spherical or rod shaped. It also relates to an air extractor (10), in particular of a motor vehicle, comprising a support (12) having at least one window defining an opening for the passage of air and at least one flap valve (14) as described above and movable between a position of closure of the opening and a position of opening up this opening.