Naturalization policies in France and the USA are not much different, but migration policies are quite different, with selective migration and a permanent residence scheme (green card) in the USA but not in France. Naturalization trends are directly affected by policy changes, including anticipation effects and structural effects like the size and composition of migrant cohorts as regards origin and type of entry visa (including regularization in the USA). Selective migration policy in the USA enables more migrants to meet the requirements for naturalization on an individual basis than in France where one third of all naturalizations are by marriage. The US green card impacts socio-economic characteristics of migrants: migrants with high human capital tend to naturalize less than people with mid-level qualification and income, probably because they can stay permanently with a green card. As part of migrant strategy, migrants often use naturalization as a form of security against low human capital or to increase their chance on the labour market. For some migrants, naturalization is part of a life course project. More migrants remain foreigners in France than in the USA. This seems to be related to France's non-selective migration.