This is simply not true. If you look at the report of the Cour des Comptes regarding the tax rates of the financial sector [1] you will see that France take less taxes on bank than pretty much all OECD countries, the only exceptions being Portugal, Spain, Finland and Austria. There are a lot of methods for banks or big company to lower taxes in France and it works well with both bank and France's interests.

[1] http://www.ccomptes.fr/Publications/Publications/Les-preleve... (in French)