Background: Migrant health is under researched in France. However, it is an important issue because of the political and economic crisis which currently produces refugee influx in European countries. Studies in health economics show that migrant health in France has decreased since 2000. Methods: Our research questions have been elaborated in collaboration with institutional agencies, especially Regional Direction of Youth, Social Cohesion and Sports, and Regional Health Agency. The forthcoming law on foreigners’ access to rights raises a number of issues among professionals in those agencies who have to implement integration policies. Foreigners’ access to rights and migrants’ access to rights are not clearly defined by sociologists, policymakers, agencies and services working in the sector. Our research is informed by three main questions: Which rights migrants do have access to? What are the barriers to this access? What are the impacts of those barriers on their health? Firstly, we analyze laws related to foreigners’ and migrants’ access to rights. Secondly, we map organizations and NGOs supporting migrants in a defined territory. Thirdly, we conduct in-depth interviews with migrants, social workers, activists and policymakers. The field work is conducted in two regions with a different immigration history. Results: Migrants come with a better health compared to the non-migrant population but the more time they spend in France, the less healthy they become. This is due to the weakness of the social rights, the ignorance of these rights by the people and their living conditions in the host country. In France, social determinants of health indicators, such as education, income, and employment are less favorable for migrants and their children compared to the other OECD’s countries. Implications: This situation has high impact on social workers who are directly working with the migrants in their living environment.