Method for manufacturing an automotive part that is intended to be located in the operating range of a radar system arranged in the motor vehicle, without interfering with the operation of said radar system in the operating condition of the motor vehicle, the part in its finished condition having an external face visible from the outside of the motor vehicle and such visible external face including a motif (50A, 50B) or area having a shiny metallic or metallised appearance, comprising the following steps: - arranging a sheet metallised with a light metal or metalloid, which has a visible face with a shiny metallic or metallised appearance, which in the finished condition of the part will be at least partially visible from the outside of the motor vehicle in the operating condition of the motor vehicle, and a concealed face, opposite the visible face; - thermoforming said sheet such that a relief corresponding to the motif (50A, 50B) is provided on the visible face; - overmoulding a first thermoplastic onto the concealed face of the sheet such that, once cured, the first overmoulded thermoplastic fills the recess created by said relief and presents a smooth free surface; - arranging one or more through-holes in the sheet and arranging one or more through-holes in the first overmoulded thermoplastic in alignment with the through-hole(s) of the sheet, such that at least one shared through-channel (2, 6) is formed; and characterised by - overmoulding a second thermoplastic onto the visible face of the sheet, through at least one shared through-channel (2, 6), in such a manner that said second overmoulded thermoplastic spreads around said relief in such a manner that a region with a shiny metallic or metallised appearance not covered by the second overmoulded thermoplastic is obtained, corresponding to the motif (50A, 50B), producing a smooth surface shared by the motif (50A, 50B) and the free surface of the second overmoulded thermoplastic. - arranging a sheet metallised with a light metal or metalloid, which has a visible face with a shiny metallic or metallised appearance, which in the finished condition of the part will be at least partially visible from the outside of the motor vehicle in the operating condition of the motor vehicle, and a concealed face, opposite the visible face; - thermoforming said sheet such that a relief corresponding to the motif (50A, 50B) is provided on the visible face; - overmoulding a first thermoplastic onto the concealed face of the sheet such that, once cured, the first overmoulded thermoplastic fills the recess created by said relief and presents a smooth free surface; - arranging one or more through-holes in the sheet and arranging one or more through-holes in the first overmoulded thermoplastic in alignment with the through-hole(s) of the sheet, such that at least one shared through-channel (2, 6) is formed; and characterised by - overmoulding a second thermoplastic onto the visible face of the sheet, through at least one shared through-channel (2, 6), in such a manner that said second overmoulded thermoplastic spreads around said relief in such a manner that a region with a shiny metallic or metallised appearance not covered by the second overmoulded thermoplastic is obtained, corresponding to the motif (50A, 50B), producing a smooth surface shared by the motif (50A, 50B) and the free surface of the second overmoulded thermoplastic.