Migrant background is a major social determinant of health. It contributes to an individual’s social position and interacts with other social determinants such as gender, education, employment, and financial resources. ; In France, migrant background has not been sufficiently studied in public health research through the lens of social inequalities in health. ; To characterize migration background, the most common approach, used by public statistics in France, relies on the collection of objective civil registry data, such as individuals’ nationality and country of birth, or even those of their parents. ; Collecting this data in health surveys makes it possible to compare the health of French nationals with that of foreigners, and of native-born (non-immigrant) individuals with that of immigrants. ; This approach helps to understand the extent to which migratory background can be a factor in social health inequalities and how these inequalities may be linked to unequal access to various resources (health services, housing, education, employment, leisure activities, public services, green spaces, etc.) and to discrimination.