Christophe Lèguevaques, lawyer at the Bar of Paris, PhD in law, specialized these last years in the right of the catastrophes and the collective risks. He intervenes in particular in the files of the accident of a plane of Air Vietnam, on-irradiation of the CHU of Toulouse [after the defective installation of a machine, 145 people received a surdose radiation. The association “SOS Irradiés 31” entrusted the file to Maître Léguevaques] and of the accident of AZF [It is about the explosion of a chemical plant in Toulouse (11 deaths, thousands injured and a lot of material destructions)]. He delivers the fruit of his experiment to us.