This chapter explores the spatial patterns of micro-scale social differentiation in two housing structures in the same block of a disadvantaged neighbourhood of central Marseille. It describes how the individual strategies of city residents, public policy, and the resilience of the urban fabric interact to produce fluid flat by flat, and building-by-building spatial patterns of social stratification. It shows that such patterns are typical features of central “arrival neighbourhoods” marked by marginal gentrification and new models of social mix policies. It also questions whether such micro-scale social differentiation can be described as “segregation”