Intergenerational housing opens new possibilities for the elderly when facing isolation. It provides a solution for an old person to organize new ways of co-living with a younger dweller in need of a cheaper rent or conviviality. This system has to be understood within a larger framework of housing for the elderly. Housing typologies (co-living, participatory housing) are also developed beyond the domestic sphere through a new habitat created by public relations between generations. The intergenerational housing “model” quite popular in many European countries has been greatly mediatized in France since the growth of the aging population and a recent housing boom in central cities. For the past ten years many organizations, mostly nonprofits, participate in creating this new type of service to build this mutual match between old and young dwellers. If some networks are starting to be gradually structured nationwide these initiatives are usually somehow fragmented while being punctually considered by the housing private sector and stimulated by local government. This phenomenon in housing services illustrates the limitations both of public policies and the housing market by designing the public realm and interests through the lens of user centered practices or even citizen centered design. Our contribution will show an experience of a “research-project” initiative using design methods and practices to promote such intergenerational housing across cultures of work and habits while understanding at the same time its scope (health, mobility, communication) and larger context of development (central cities, rural areas). This “research-project” is located in the south of France and developed by a research team of social innovation by design (Projekt Research Lab) at the University of Nîmes.