It is important to distinguish between the idea of the "precautionary principle", a precise concept that made its appearance under specific circumstances in the 70s in order to respond to certain environment-related issues and the idea of "precazltion", itself move or less confused with the idea of "caution", a term used to describe a general attitude to risk and uncertainty. Although it is easy to identify the notion of "precaution" with a general philosophy of responsibility, the "precautionary principle" has no meaning except when used to describe public precautionary policies. And though we cannot give a precise definition gf the idea or precaution, in the sense of caution, we can however give a precise description of the "precautionary principle", based on the techniques, always specific which are implemented in rite name of the precautionary principle In France we hare developed the habit of considering precautionary actions as part of an overall moral principle, while totally disregarding the laws defining the "precautionary principle" and including if within the power framework of state policy. It is essential to clear up this confusion, along with all of its potentially dangerous legal consequences, before we can envisage an informed discussion on the "precautionary principle", its field of application and the conditions governing its implementation.