[en] Return of experience on Chernobyl post-accident management: the PAREX study Belarus is the country the most affected by the Chernobyl fallouts and is among the most significant experiences in the nuclear post-accident field. Despite specificities inherent to the political and social situation in Belarus, the experience of post-accidental management in this country holds a wealth of lessons in the perspective of preparation to a post-accidental situation in the French and European context. Through the PAREX project (2005-2006), the French Nuclear Safety Authority analysed the return of experience of Chernobyl post-accident management from 1986 to 2005 in order to draw its lessons in the perspective of a preparation policy. The study was led by a group of experts and involved the participation of a pluralistic group of about thirty participants (public authorities, local governments, NGOs, experts, operators). PAREX highlighted the complexity of a situation of long-lasting radioactive contamination (diversity of stakeholders and of dimensions at stake: health, environment, economy, society...). Beyond traditional public crisis management tools and frameworks, post-accident strategies also involves in the longer term a territorial and social response, which relies on local capacities of initiative. Preparation to such process requires experimenting new modes of operation that allow a diversity of local actors to take part to the response to a situation of contamination and to the surveillance system, with the support of public authorities. The conclusions of PAREX include a set of recommendations in this perspective. (authors)