Luminous warning system for a primary automotive vehicle, said luminous warning system comprising: - a detection system for computing the relative position with respect to the primary automotive vehicle of at least one secondary automotive vehicle and for transmitting relative-position-related information; - a display surface located on a surface intended to form an outer surface of the primary automotive vehicle; - a luminous device for displaying at least one stereoscopic image on the corresponding display surface, the stereoscopic image forming at least one luminous pictogram with a warning function; and - a control module for receiving the relative-position-related information transmitted by the detection system and for configuring the luminous device, and the stereoscopic image that it displays, depending on this relative-position-related information; - a processing unit configured to compute the distance separating the primary automotive vehicle from the secondary automotive vehicle, in which system said luminous device comprises: - at least one light source configured to be able to emit at least one light beam; - at least one luminous cell, each luminous cell comprising: ∘ a waveguide arranged to transport at least part of the at least one light beam emitted by the corresponding light source between a first end located on the side of the light source and a second end; ∘ at least one diffraction grating located at the second end of the waveguide, at least some of the diffraction gratings being illuminated by at least some of the light beams transported by the waveguide in order to generate at least one diffraction lobe, characterized in that the control module that configures the luminous device is then capable of receiving distance and/or position information, in order to be able to generate dynamic stereoscopic images, the content and/or appearance of which is variable and depends on the position and/or distance of the secondary automotive vehicle with respect to the primary automotive vehicle. - a detection system for computing the relative position with respect to the primary automotive vehicle of at least one secondary automotive vehicle and for transmitting relative-position-related information; - a display surface located on a surface intended to form an outer surface of the primary automotive vehicle; - a luminous device for displaying at least one stereoscopic image on the corresponding display surface, the stereoscopic image forming at least one luminous pictogram with a warning function; and - a control module for receiving the relative-position-related information transmitted by the detection system and for configuring the luminous device, and the stereoscopic image that it displays, depending on this relative-position-related information; - a processing unit configured to compute the distance separating the primary automotive vehicle from the secondary automotive vehicle, in which system said luminous device comprises: - at least one light source configured to be able to emit at least one light beam; - at least one luminous cell, each luminous cell comprising: ∘ a waveguide arranged to transport at least part of the at least one light beam emitted by the corresponding light source between a first end located on the side of the light source and a second end; ∘ at least one diffraction grating located at the second end of the waveguide, at least some of the diffraction gratings being illuminated by at least some of the light beams transported by the waveguide in order to generate at least one diffraction lobe, - at least one light source configured to be able to emit at least one light beam; - at least one luminous cell, each luminous cell comprising: ∘ a waveguide arranged to transport at least part of the at least one light beam emitted by the corresponding light source between a first end located on the side of the light source and a second end; ∘ at least one diffraction grating located at the second end of the waveguide, at least some of the diffraction gratings being illuminated by at least some of the light beams transported by the waveguide in order to generate at least one diffraction lobe, ∘ a waveguide arranged to transport at least part of the at least one light beam emitted by the corresponding light source between a first end located on the side of the light source and a second end; ∘ at least one diffraction grating located at the second end of the waveguide, at least some of the diffraction gratings being illuminated by at least some of the light beams transported by the waveguide in order to generate at least one diffraction lobe, characterized in that the control module that configures the luminous device is then capable of receiving distance and/or position information, in order to be able to generate dynamic stereoscopic images, the content and/or appearance of which is variable and depends on the position and/or distance of the secondary automotive vehicle with respect to the primary automotive vehicle.