The precautionary principle convey one nine psychology which is to integrate prevention policy within the parameters of action or decision in case of unknown risk or can’t be achieved in a never or only very distant future. Law does not recognize the significance of the precautionary principle unanimously. In fact, there is a difference between international and European courts, France respectively. Currently it is illustrated in several fields privileges: health protection and food safety, GMOs, mobile telephony, the use of substances and risk products.