Since most of researches on economic metropolization have until then concentrated on "high added value" workers on both sides of the border, little place is left neither for analysis of the less valued categories in the process of metropolization, nor for the diversity of jobs within the regional labour markets. Yet, what is the position of less favoured social categories in the evolution of cross-border metropolis during last decades, when compared with managers or other liberal professions? To answer this question, a case study is carried out on the cross-border commuters in the Lorraine Region (France) who participate in great numbers in the metropolization of Luxembourg, by comparing them to those who work in France. The objective of this article is to give an account of the spatiotemporal evolution of main social classes among the cross-border commuters, based on the French population censuses. These databases are, from 1968 to the present day, comparable both in the time and space. The results confirm that a cross-border metropolis of Luxembourg is formed, notably since 1990s, by a substantial increase of highly qualified cross-border commuters, as well as by an augmentation of less qualified workforce during this period: thus, in the Region of Lorraine, even in 2013, the share of the cross-border working class (to Luxembourg) remains greater than it of the working class within France. Moreover, complex links exist in the phenomenon of metropolization between historical social segregations and the specific metropolitan segregations in terms of socio-spatial organisation of the territory in question: for example, the secondary urban centres of the French metropolitan area, such as Thionville or Metz, play a role of the residential reservoir for the most highly qualified cross-border commuters, especially when this type of workforce has already been observed in these agglomerations in the past. The first results assume to learn more about the conditions of different residential trajectories, meanwhile, the ...