Abstract: The construction element comprises a profile frame, a filler material and two cover panels which cover the filler material and the profile frame. The profile frame comprises a profile section having an axially symmetrical cross-section which forms a groove-like recess in which a connector element is frictionally engagingly insertable and arrestable. In a building construction system with construction elements erected, the construction elements are fastened on one side to a framework, connected with another construction element on the opposite side by the connector element and supported on the edge of the third side. These construction elements can be assembled in the manner of a construction set, for instance like a child's toy (Lego) and the requirements for tools and plant are very modest.