Before The Charter of the Environment became the supreme hierarchical reference of our legal System, the environmental tax System had to face constitutional fiscal principles. In several instances, the Constitutional Council had to invalidate legislation on ecological taxes by referring to the principle of the equality of tax payers. Being integrated in the preamble of the Constitution, the Charter of the Environment was hailed by the Doctrine as allowing considerable reinforcement to the basis of eco-taxation. In fact the Constitutional Council was rather silent : so it may be asked whether the Charter of the Environment was really helpful toward ecological taxation.