Flemish emigration during the nineteenth and twentieth centuries is too complex to be dealt with definitively in a single article. Our main objective is to provide an overview of the migration towards France and Wallonia by looking at its chronology, and the spatial distribution of emigrants and their descendants. In this effort, patronym distribution is very helpful. As markers of migratory movements, patronyms from a collection of nominative lists give us a handle on migration flows as no other evidence can. Comparing France and Wallonia, the two destination areas, it is possible to see similarities between types of migrants: workers in heavy industry, workers in the agricultural sector, and workers engaged in domestic services. In addition, three phases may be identified in the arrival of a Flemish population in France and Wallonia: an emigration phase, an integration phase, and a redistribution phase. The last phase is also part of the urbanization process and is linked with upward social mobility.