Cities dealing with housing shortages are increasingly adopting urban recycling, a strategy that repurposes existing buildings and structures to create new housing without using additional land. This approach includes lifting buildings, converting commercial spaces like offices and shops into homes, and reconfiguring current housing to better suit modern needs. In Rennes, France, the Rennes metropolitan area has chosen to recycle two twin towers on rue du Bourbonnais, constructed in the late 1960s. These towers, standing nearly 30 meters tall, have been vacated by their occupants between 2023 and 2025 to make way for new residents. The project involves cleaning the buildings, preserving their structure, and converting large apartments into smaller units to match today’s smaller household sizes, which have dropped from an average of four people per unit to 1.8 people. This effort is expected to increase the number of housing units in the towers from 165 to 211. Urban recycling also includes building elevation, a technique that allows for increased density without expanding land use. This method, often compared to stacking Lego bricks, has been tested in several cities, including Rennes, where scans of 94,000 buildings across 43 communes have identified potential for elevation in more than half of them. In addition to elevation, cities are repurposing vacant buildings such as old schools and post offices into housing. For example, in Nouvoitou, an old school has been converted into apartments and single-family homes, while in Saint-Armel, an old post office has been transformed into a residential building. In Paris, the newly elected mayor Emmanuel Grégoire has prioritized addressing the housing crisis through urban recycling strategies. The city has adopted a policy of zero net artificialization, which means no new land will be used for development. Paris is targeting empty offices and vacant housing, with plans to double the tax on such properties next year. The city has also been purchasing degraded private buildings and rehabilitating them into social housing. Former parking lots and garages are being transformed into social residences, reflecting a broader strategy of repurposing existing spaces to meet housing needs. The Rennes metropolitan area has set a goal to deliver 3,000 social or private housing units through real estate recycling between 2023 and 2028, which represents 10% of the new housing supply. These initiatives highlight a growing trend in urban planning that seeks to address housing shortages by creatively reusing existing infrastructure rather than expanding into new areas.