Bumper assembly for motor vehicle, motor vehicle end portion comprising such an assembly and motor vehicle

The assembly (10) has an energy absorbing panel (12) provided with two energy absorbing columns (16), each bearing at ends of upper and lower side members (6, 8). An energy absorbing beam is transversely extended between the columns. A metal plate (36) doubles the beam such that the beam is compressed between a frontal face (36a) of the plate in case of impact. A metal stage (34) doubles each column such that the column is compressed against a front face (34a) of the stage in case of impact. The panel is obtained in a single piece by injection molding of plastic material.