The building on Cugnot street in Saint-Etienne offers a flexible 16-storey structure placed on a small plot, capable to accommodate appartements, offices and shops by ensuring significant operating economy. The energy consumption for its occupants will be equal to 0 €. Its energy balance is positive: nearly 1,400 m² of photovoltaic panels on facades and roofs, reuse of rainwater, “triple flow” hybrid ventilation. The project also benefits from the FLEXI FLOOR hybrid technology – made up of wood and low carbon concrete, which allows office-housing reversibility.