A luminous false-wall device, comprising: a chassis constituted by at least one profile, the chassis comprising an upper part directed toward a panel to be covered, such as a wall or ceiling, and a lower part; a diffusing canvas fixed on the chassis and stretched on the lower part of the chassis; a light placed between the panel and the canvas configured to emit light in the direction of the canvas; wherein the chassis is provided with means of increasing the light intensity of the light.