In the small town of Firminy, about fifteen kilometers from Saint-Étienne, the population has been steadily decreasing for decades. Once a hub of the steel industry, the area has seen many factories close, leading to economic decline. Many residents have either moved closer to Saint-Étienne for work opportunities or have left altogether, seeking a better quality of life in the nearby countryside of Haute-Loire. Despite these challenges, Firminy still holds a unique piece of architectural history that stands as a symbol of its past. At the heart of Firminy is the Firminy-Vert site, a complex of buildings designed by the renowned Swiss architect Le Corbusier. The centerpiece of this development is a towering concrete structure, often referred to as a housing unit, that is both imposing and distinctive. This project is notable not only for its design but also for its social purpose—two-thirds of the apartments are HLM, or social housing, meant to provide affordable living spaces. The buildings are considered a piece of architectural heritage, with their façade and roof terrace officially classified as historical monuments since 1993. However, the design of the buildings, which dates back to the 1960s, has become a challenge in the face of modern climate conditions. The structures were not built with today’s extreme temperatures in mind, and during recent heatwaves, the apartments have become uncomfortably hot. Without features like window shutters to block the sun, the buildings are turning into ovens during the summer months. Because the site is classified as a historical monument, there are limited options for making the buildings more energy-efficient or comfortable for current residents. This situation has led to growing concerns among the residents who call the tower home. Many are frustrated by the lack of solutions to the heat problem, especially since the buildings are protected and cannot be easily modified. Despite these challenges, the Firminy-Vert site remains a significant part of the town's identity, a testament to the vision of an architect who sought to blend modernist design with social responsibility. For now, the residents continue to live in a structure that is both a historical landmark and a reminder of the challenges of adapting old designs to a changing world.