Motor-vehicle seat provided with a system for supplying conditioned air

In a motor-vehicle seat the padding body (1, 1') of the cushion and/or the backrest has a passage for the air coming from the air conditioning system (7) of the motor-vehicle. This passage comprises a closed cavity defined between a lowered surface formed in the outer surface of the padding body and the seat cover (3). At least part of said closed cavity is separated from the cover (3) through a layer (2, 200, 2', 200') of a material substantially impervious to air, adapted to exchange heat by thermal conduction, through said cover (3) with the body of the occupant.