This thesis examines the roles of migrant networks in the migration and subsequent economic integration of Senegalese men and women in France, Italy and Spain. It challenges the assumption that networks are invariably sources of assistance in the migration process and examines the factors responsible for variations in their influence. In doing so, it uses quantitative methods and analyzes recently collected longitudinal data within the framework of the Migration between Africa and Europe (MAFE) project. Migrant networks -– members of the respondent’s personal circle that have international migration experience – are conceptualized as a form of individual-level social capital that may or may not shape specific outcomes. The thesis contributes to the literature by adopting a longitudinal view of the migration process and considering both migration behaviour and migrants’ labour market trajectories at destination. In doing so, it bridges two areas of research that have mostly developed separately. Second, the intersections between migrant networks and gender, insufficiently studied so far, are here examined in detail. Furthermore, the role of networks in different forms of female mobility – often confounded in previous work - are here analysed separately. Last but not least, the thesis makes a methodological contribution by operationalizing migrant networks in a more dynamic way than previous work. Findings suggest that migrant social capital has a large influence on migration behaviour, while playing a lower and more ambivalent role in migrants’ labour market outcomes at destination. Furthermore, several dimensions are found to shape the extent and channels of networks’ influence. First, men and women do not rely on the same ties in their migration process. Also, women migrating independently of a partner make a different (and greater) use of their migrant connections than those joining their spouse abroad. Migrant social capital is found to work along gender lines: only access to male migrant networks increases the migration likelihood or the job prospects at destination for prospective male migrants. On the other hand, female networks play a crucial role in independent women’s migration process. However, while they greatly increase women’s likelihood of moving to Europe on their own, they also lead them to lower-status jobs. Last, the context of destination was found to shape the operation of migrant networks. In France, where a socio-economically diverse Senegalese community has long been established, pre-migration ties at destination lead to better economic opportunities. In contrast, migrant networks in Italy or Spain appear to channel male migrants into street-selling activities. Thus, bonding social capital in the form of migrant networks appears to reproduce the ethnic niches developed at destination and the gender-segmented nature of the labour market.

A l'interface de la sociologie des migrations et de la sociologie politique, la thèse porte sur les migrations de retour des réfugiés congolais à partir des principaux pays d'acceuil l'afrique centrale. loin d'être regardées dans une perspective linéaire et statique entre deux sédentarités mais analysées à partir d'observation in situ et d'entretiens biographiques réalisés pendant près de seize mois dans les espaces d'accueil et de retour, les migrations de retour son intégrées ici dans un espace migratoire dynamique fait d'oppositions et de transactions entre les dispositifs du flux migratoire qui organisent et réglementent les migrations de retour, et les multiples pratiques formelles et informelles du sujet dont les intenses jeux de tension s'inscrivent dans un contexte soutenu de limitation des flux migratoires et l'accroissement de nouvelles formes de mobilité dans l'espace migratoire d'afrique centrale. / In the interface of the sociology of migration and political sociology, the thesis focuses on return migration of Congolese refugees from the main host countries of central Africa. Far from being observed in a linear and static perspective between two sedentarinesses but analyzed starting from in situ observations and from biographical interviews conducted during 16 months in host and return areas, the migrations of return are integrated in a dynamic migratory space constituted by oppositions and transactions between the biopolitic plans of retention of flows and the circulatory practices of the refugees. The accent is particularly focused on negotiating "biographical crossroads" and migratory careers of refugees from the social, spatial and political capital acquired during the refuge time. How, in these intersections between migratory careers and biopolitical plans, the returnees can define and negotiate their installations in the environment of return ?