France has 14,930 periurban communes (a commune is the lowest tier of local government in France) that cover one-third of the territory, among which 90% are rural communes. The periurbanisation movement is often associated with social segregation in cities. We explain the reasons behind this. For two decades, the average commune income per household has progressed in the periurban areas and declined in the urban centres, showing a relative enrichment of these areas. However, executives are more centrally located than workers, who are overrepresented in the more distant periurban communes. Moreover, we observe an intensification of segregation within the urban hubs.