This article aims to evaluate the net contribution of immigration to the public finances of France between the late 1970s and the early 2010s. We developed an accounting method that disaggregates the primary deficit into the specific contributions of immigrant population and native population. We show that the net contribution of immigrants is generally negative over a relatively long period, but remains at an extremely low level (+/-0:5% of the french GDP, reduced to +/-0:2%, with the exception of 2011). The relatively negligible effect of immigrants on the public accounts is explained by a favourable demographic structure offsetting their lower net individual contribution. However, the 2008 financial crisis has significantly degraded the economic condition of immigrants. The net per capita contribution of EU immigrants has significantly declined since 2000 and is now similar to values from third country immigrants.