[dakdak]

There's a much broader project that can compute most taxes and benefits for France (and a few other countries) : https://github.com/openfisca/openfisca-france

It would be quite interesting to check that both the French IRS implementation of the tax & benefit laws and the free software community (though most devs of the project were employed by the French admnistration) implementation of the tax and benefit laws actually output the same results.