The French tax legislation uses the word « sanctions » to qualify at once tax penalties, applied by the administration, and the penal sanctions, pronounced by the criminal judge. The French courts consider that both have in common a dimension of punishment, which requires that they be motivated, and the deep contemporary dilemma lies in the possibility of making a cumulative application of them. European and French courts had to give an interpretation of the principle ne bis in idem. If the tax penalties respect a unified regulation, the penal sanctions try to punish the different contemporary manifestations of tax evasion.Les sanctions applicables en matière fiscale en France se subdivisent en deux grandes catégories : les sanctions fiscal...