Device for covering a motor vehicle floor

The device (1) has an elastic covering layer (3) made of felt or foam. A plastic molded structure (4) is equipped with a plate (5) for receiving a covering layer and a mounting unit (6). An elastic decoupling layer (7) is placed against a floor. The mounting unit is rested on the decoupling layer. A rear face (8) of the plate is equipped with a rib network (9) projecting toward downward direction. A porous layer (10) of an acoustic absorption part is mounted against the rib network so as to isolate the porous layer from the rear face.