Journal article: This article offers a new approach of the microsimulation analysis of fiscal systems thnks to a model including four major French taxes and the bootstrap technique. We compare the redistributive impact of an increase in fiscal revenue for different fiscal instruments and confirm the well-known result of the strongly redistributive impact of the income tax and the regressive one of the VAT. our methodological contribution consists in the construction of confidence intervals for the semi-elasticities of the Gini coefficients to the use of each tax.