Les divisions socioprofessionnelles en mouvement d’une métropole attractive. Le cas de l’aire urbaine de Nantes (1975-2015)

Within the field of urban studies, quantitative research on the assessment of social and urban segregation mainly focuses on the Paris case. Research is also characterised by little historical depth, due in particular to the methodological difficulties corresponding to such an approach. This paper presents a diachronic analysis of the social segregation of the Nantes metropolitan area over forty years (1975-2015). It adopts a quantitative approach combining tools and processes that are often addressed separately. The first part of the paper uses segregation and dissimilarity indexes to measure the evolution of segregation between social groups; it demonstrates the decline in these indexes since the 1970s. The second part uses a combination of multivariate statistical methods (Principal component analysis, Hierarchical classification analysis, Sequence analysis) in order to provide a spatial typology of the successive patterns of urban segregation. These analyses bring evidence of the gentrification dynamics, which concern some central areas in the Nantes metropolitan area. Besides, they highlight the social mix configurations that prevail in most neighbourhoods and municipalities of the metropolitan area. While the urban spatial fragmentations are often mentioned without being empirically grounded, this paper brings a series of quantitative evidences concerning current crucial French political issues and debates.