Since the 1990s, the process of metropolisation and the generalised use of “Mobility” coincided, but not by chance. In fact, the development of urban space is in permanent interaction with the practice of spatial mobility and social mobility among social actors. By focusing on the relationships between the different forms of mobility in the context of metropolisation, this thesis proposes to study the inter-mobility relationships from the systemic approach according to which these protean mobilities are considered as various forms of THE Mobility. For this purpose, we carry out our study with cross-border workers who live in Lorraine (France) and who work in Luxembourg. A mixed methodology is applied in our analyses. On the one hand, relying on intercensal dataset of the French population, our macro-social analyses confirm a trend of socio-residential segregation, by highlighting not only the process of gentrification at the metropolitan scale, but also the phenomenon of the “residential abandonment” in terms of daily mobility. In addition, our socio-spatio-temporal categorisation completes the definition of long-distance commuting within a relational model. On the other hand, we investigate the representations and practices of the different mobility of the Franco-Luxembourgish cross-border commuters. Our microsocial analyses show that commuters consider the cross-border daily mobility as a tool favourable to their residential mobility outside the metropolis and to their socio-professional mobility within the metropolis. These three mobilities are rather interrelated than being independent of each other. However, such a socio-cognitive configuration of the instrumentalisation of daily mobility is socially structured : for some, the cross-border commuting serves as a support for ascending social mobility, while for others it only allows to avoid social downgrading. ; Le processus de métropolisation et la généralisation de l’usage du terme « mobilité » coïncidaient depuis les années 1990 mais non par hasard. En ...