This first issue of the Cahiers de la Chaire Immobilier et Développement durable takes a look at the changes in society and real estate that are transforming our towns and cities. Interviews with some twenty academics and actors from the real estate sector highlight the issues facing different real estate sectors in a context of fast-paced change in our societies. The rise of mobility, the digital revolution, new ways of working, new consumer habits, cultural practices, an ageing population, the demand for flexibility in the world of work… all these social and cultural mutations are factors for change in our relations to space, and built-up space in particular. How should the housing, offices, and warehouses of tomorrow be designed today? Are these very classifications called into question by the emergence of new forms of hybrid buildings intended to meet the need for coherence in urban organization? As environmental constraints grow increasingly stringent, what innovations today point to areas for reflection on the city of tomorrow?