Assembly of damper doors

The flap arrangement (1), especially for a ventilation system of a motor vehicle, has at least two flaps (3,4) which have a section in the form of a hollow cylinder section, whereby one flap is fitted inside the other. The two flaps have the same pivotal axis (5). The inner flap (4) has at least one opening (7) with at least one curved side (7c). If there two curved sides, their middle points are located in the outer region of the hollow cylinder section. An independent claim is included for a use for the proposed flap arrangement which is in the ventilation system or air conditioning system of a motor vehicle.