[en] A first set of articles addresses the nuclear crisis in Japan (description of the accident, information mission sent by France, and support actions undertaken by France in Japan in the fields of education, civilian security, culture, sailing, media, dosimeters, robotics). A second set discusses lessons learned in terms of nuclear safety (complementary safety assessments, stress test in Gravelines), radiological consequences (impact on Japanese population, the Symbiose software, the Teleray network), crisis management, and research