The Sufficiency Action Hub aims to demonstrate the necessity, feasibility, and social desirability of sufficiency measures in the building sector, fostering a shared understanding across decision-making levels. Its goal is to build a diverse community of stakeholders worldwide, from various sectors of the building value chain, to adapt sufficiency solutions to different contexts, recognizing disparities between the Global North and South. Launched by the French Institute for Building Performance and supported by key institutions like ADEME, the initiative seeks to address the environmental challenges posed by the building sector, which is responsible for 21% of global greenhouse gas emissions. The Action Hub highlights the urgent need for sufficiency measures, advocating for a systemic approach that integrates demand-side policies to reduce resource consumption, mitigate emissions, and ensure social equity. Through international collaboration and the adoption of the "Sufficiency First" principle, the initiative aims to reshape the future of the building sector within planetary boundaries. The Action Hub has recently published a report outlining the key findings of its ongoing work and initiatives.