The objective of this study is to use both static and dynamic frameworks to compare the benefits that immigrants draw from the public system with their contributions through the taxes that they pay. The main conclusion of this paper is that the impact of immigration on welfare systems is weak. Thus, if we compare, on a given date, immigrants' global contribution to the public administration budget with the volume of transfers they receive, immigrants appear to be relatively favoured by the redistribution system. At the same time, even if immigrants seem to pay less taxes and receive more transfers than natives, the difference in distribution between the two populations, with a higher concentration of immigrants in the active age groups and a sparser concentration among the net beneficiaries of the social transfer system, leads to a slightly positive long‐term impact of immigration on public finances. However, the impact of immigration remains very slight compared with the global effort that would have to be undertaken to reduce budgetary imbalances.

Immigration, Welfare, Computable general equilibrium, J61, I3, D58,

International audienceImmigration is often seen as an instrument of adaptation for ageing countries. In this paper, we evaluate, using a dynamic general equilibrium model, the contribution of migration policy in reducing the tax burden associated with the ageing population in France. Four alternative scenarios, compared with a baseline scenario based on official projections, are simulated with the aim of quantifying the effects of immigration on French social protection finances. We show that the age and, to a lesser extent, the skill structure of immigrants are the key features that mainly determine the effects on social protection finances. Overall, these effects are all the more positive in the short to medium term if the migration policy is selective (in favour of more skilled workers). In the long term, the beneficial effects of a selective policy may disappear. But whatever the degree of selectivity of the migration policy, the financial gains from higher consequent migration flows are relatively moderate compared with the demographic changes implied by ageing