The renovation of the Palais des Nations, developed by our founding partners at group8, is a complex construction project with phasing managed on an operational building in a short amount of time. The renovation focused on improving the building's energical and environmental performance to obtain the Minergie® label and comfort users. The building's envelope advanced with 1050 new windows following the original designs. A large portion of the roof was sanitary engineered, and 2800 m2 of photovoltaic panels and 210 m2 of thermal panels were installed. Architects acknowledged the building's conspicuous architectural heritage for all changes.