Since 2015, France has been faced with terrorist attacks and their effects, tragic events that transform social relationships, increasing tensions that are already present within poor neighborhoods, inhabited by persons coming mainly from an immigrant background, many of them being of the Muslim faith. In this article, being in a position of “witness-interpreter,” the author reports on significant situations connected to these evolutions and social, political, identity-related tensions in these neighborhoods. The author proposes and develops a workstream, to which psychosociologists are contributing: “collective reassurance,” a process implemented with the inhabitants—young adults, professionals, local elected officials . . .—that aims to support collective abilities to transform situations of breakdown and fragmentations within this difficult environment.