[en] In the framework of the reduction of the carbon dioxide emissions in the air, the underground storage of the CO₂ is studied. Some experimentation are already realized in the world and envisaged in France. This document aims to study the juridical aspects of these first works in France. After a presentation of the realization conditions and some recalls on the carbon dioxide its capture and storage, the natural CO₂ underground storages and the first artificial storages are discussed. The CO₂ waste qualification, in the framework of the environmental legislation is then detailed with a special task on the Lacq region. The problem of the sea underground storages is also presented. (A.L.B.)