Fixing device (30) for a windscreen wiper actuation linkage system, this device comprising a plate (32) intended to be fixed onto a vehicle body (36), and at least one locking member (34) intended to cooperate with said body to lock the fixing of the plate onto the body, characterized in that said plate is configured to be displaced in translation in the joint plane with said body, and in that said locking member is mobile, deformable or displaceable from an unlocking position to a locking position.