This article discusses aspects of stability and instability in the social hierarchy of French urban housing over time. The analysis is based on the creation of housing categories using the occupancy characteristics of 58 types of housing units. Each category represents the position of a housing unit and its occupant in a socially hierarchized residential space. Our study looked at the movements of housing units between these different positions, the residential distribution of 11 cohorts of households and the residential trajectories of social groups from 1978 to 1996. Its results highlight the emergence of a twofold residential contrast — between the top and the bottom of the social hierarchy, and between the generations who benefited from economic growth during the period known as the Trente Glorieuses and other generations. These contrasts are expressed through a significant erosion of the most socially mixed sections of the housing stock, most recently through increasingly rigid channels of access to housing, and through upward residential trajectories that now exclude working‐class social groups and are no longer totally guaranteed to young households in the higher social groups.