Does Immigration have an Effect on Public Finance ? This paper tries to assess the impact on public finance of an immigrant coming to France. It enlightens the advantages of a dynamic approach, in which all taxes and social protection benefits are taken into account along the life cycle and illustrates in particular the potential contribution for public finance from young, qualified immigrant workers. The impact of immigration on public finance is difficult to determine, but whether positive or negative, its magnitude seems to be small. In the long run, the advantage coming from the fact that ages where people are on the labour force are strongly represented among new migrants is offset by the fact that they are less educated than young na...