THE COLLECTIVE ACTION: A collective action is a group defence. There are as many individual applications as there are applicants, but the same lawyer manages these different procedures. Interest: in the amicable phase, collective action increases the chances of obtaining damages and interests. During the litigation phase, since disputes concern similar issues, the research and drafting of arguments is reduced for each file (since it is mutualized). Another environmental interest, for example, may be to mutualize the cost of the expertise needed to demonstrate the harmful event or the harm or causal link between these two elements. Ex: I have lung disease because of a malfunctioning incinerator near me. My neighbours have lung disease. I can request an analytical report attesting to the causal link between this pathology and the inhalation of toxic dust resulting from waste incineration. This report may be used by each applicant to demonstrate the responsibility of the incinerator operator. The collective action is possible in terms of liability, before the civil court (when it is a company that is at the origin of the damage) but also before the administrative court (when it is a public person who is at the origin of the damage), or before the criminal court (when the fact at the origin of your damage is a crime or a felony). THE CLASS ACTION: The class action, is a specific procedure provided by law, which allows an association or trade union to exercise on behalf of several persons a legal action against the authors of a damage Attention, it is not just any association: the law provides that only certain associations can carry such actions (approved or existing for more than 5 years in particular). These actions carried out by associations or unions are only possible in certain areas, in particular consumption, the environment and health. The disadvantage: it involves going through a third party (strictly defined) who centralizes the appeals. Moreover, it does not always make it possible to individualize the damage. It also deprives the plaintiffs of their autonomy (if the association bringing the action decides to accept the amicable agreement or not to appeal the judgment, the plaintiffs are obliged to comply with this decision).