At Paris (XVIIth), the architectural firm LBBA-Architecture completed in 2026 the renovation of a 1960s office building designed by Bernard Zehrfuss for the Caisse Centrale du Crédit Mutuel. The building, located in the busy residential area of Plaine Monceau in the 17th arrondissement, was originally constructed to house the headquarters of a climate engineering company called Tunzini before being acquired by Crédit Mutuel in 1991. Zehrfuss, a well-known architect of the post-war period in France, was known for his innovative designs and focus on functional workspaces. The original structure included a first volume built in 1961 with nine levels above ground and five below, followed by a second addition in 1968 that expanded the office space to over 6,800 square meters. The renovation project aimed to preserve the building's overall structure, including its concrete and steel framework, floors, and original facade design, while adapting it to modern needs. The building's base was redesigned to create a path leading to a garden, with patios and double-height spaces allowing more natural light to enter previously dark areas. The updated layout includes flexible spaces like a Work Café, auditorium, lounge, and collaborative work areas, helping the building better connect with its surrounding environment. A central atrium provides natural light and open views, while modular partitions allow for adaptable floor plans. Features like balconies, sliding windows, and green terraces on each floor extend the workspace outdoors, promoting comfort and interaction. To improve energy efficiency and natural lighting, the project replaced the old aluminum curtain walls with Wood Frame Facades (FOB), which were designed and assembled in a workshop in Meximieux (69). This off-site construction method helped reduce costs, delays, and the building's carbon footprint. The new facade mimics Zehrfuss's original design through a repeating pattern of 1.10-meter sections, including balconies. The wooden frames are made from pine from the Jura forests, with recycled aluminum inserts and insulation made of wood fiber. These materials complement the existing concrete and steel, creating a warm, calm atmosphere. On the rue Cardinet side, the facade features extruded triangular aluminum profiles in a champagne color, which reflect sunlight and create a dynamic visual rhythm throughout the day. Horizontal blades on the facade also help reduce summer heat without using high-tech systems. To address urban heat and improve outdoor spaces, the project transformed 800 square meters of previously unused rooftops and patios into accessible green areas. A vertical garden connects the ground floor to the R+8 level, starting with a full garden at the back of the site. Terraces feature layered plantings, including climbing plants, flower beds, and planters, promoting biodiversity. External stairs link the different levels, creating a path that encourages informal interactions and well-being. This integration of nature into the building's design aims to enhance both environmental sustainability and the quality of life for its users.