Abstract: Polygonal panel for a wall or ceiling cladding of the type in which certain longitudinal edges of the panels rest on supporting devices or are wedged in by the latter. The panel has a metal front plate, a metal rear plate and a core joined thereto, e.g. by adhesive, composed preferably of lightweight, e.g. fibre, material having non-flammable or fire-retarding and/or sound absorbing properties. The front plate is formed with at least two longitudinal side flanges which are bent over or turned over towards the rear of the panel, at least partly to enclose the core at at least two longitudinal sides. The flanges are provided with adjoining free edge parts being over or turned over outwards at an angle.