A construction element of reinforced-concrete panel (1) in which is embedded a reinforcement framework includes at least one main framework layer extending along a tensioned outer face (11) of the element (1) and to which an inner framework (3) is attached for securing to the concrete, extending to the thickness of the element (1), the latter being produced, after the placement of the reinforcement framework, by pouring concrete onto a thin continuous wall (2) forming a sacrificial formwork. The thin wall (2) forming the sacrificial formwork extends along the tensioned face (11) of the element (1) and at the same time forms the main framework layer of the element (1), the nature and thickness of the thin wall (2) being determined so as to withstand the tensile stresses generated by the forces applied to the element (1) without the risk of separation from the concrete.