It consists of the "cell façade", newly designed by CollignonArchitektur. Its solutions, in terms of technical construction, building physics and architecture, are an innovative development of the double façade. This façade is part of the overall ecological concept of the building. It saves energy and improves thermal comfort in winter. It also provides sound insulation with natural window ventilation at this highly congested intersection. The sustainable concept allowed the authorities to approve a very high land usage density for this compact office and commercial building. An integral part of the architecture is the lighting design of the façade.