Trim part of a body shell of a motor vehicle, - having a base body, which has a visible side facing towards the outer side and an inner side and which comprises a light window in the form of a light-transmitting transparent or translucent region at least in a subregion, and an opaque region with a colouring coating at least in a subregion, - having an illumination function, which is arranged behind the visible side of the base body for shining through or illuminating the light window, - having a device which has a visible side that has a colouring coating, the device being connected adjustably to the base body in such a way that in a first position the device closes the light window and fully covers the illumination function as seen from the outer side and the visible side is orientated towards the outer side, and in a second position it uncovers the light window and the illumination function as seen from the outer side, in such a way that the illumination function is visible through the light window as seen from the outer side, characterized in that the device has at least one slide element mounted longitudinally displaceably on the base body with a head section forming the visible side and a conical section formed on the rear side of the head section, the light window being configured as a through-recess formed in the base body, which is configured with a conical section for flush reception of the head section of the slide element in the first position, and the slide element being held in the second position at least with the head section extended towards the outer side, so that a light-transmitting gap is created between the slide element and the light window, and in that the base body is free of a colouring coating in the region of the conically configured recess and forms a light exit face for the illumination function. - having a base body, which has a visible side facing towards the outer side and an inner side and which comprises a light window in the form of a light-transmitting transparent or translucent region at least in a subregion, and an opaque region with a colouring coating at least in a subregion, - having an illumination function, which is arranged behind the visible side of the base body for shining through or illuminating the light window, - having a device which has a visible side that has a colouring coating, the device being connected adjustably to the base body in such a way that in a first position the device closes the light window and fully covers the illumination function as seen from the outer side and the visible side is orientated towards the outer side, and in a second position it uncovers the light window and the illumination function as seen from the outer side, in such a way that the illumination function is visible through the light window as seen from the outer side, characterized in that the device has at least one slide element mounted longitudinally displaceably on the base body with a head section forming the visible side and a conical section formed on the rear side of the head section, the light window being configured as a through-recess formed in the base body, which is configured with a conical section for flush reception of the head section of the slide element in the first position, and the slide element being held in the second position at least with the head section extended towards the outer side, so that a light-transmitting gap is created between the slide element and the light window, and in that the base body is free of a colouring coating in the region of the conically configured recess and forms a light exit face for the illumination function.