In the collective imagination, notably since the 9/11, radicalization and violent extremism were mostly linked to jihadism. However, it is a multifaceted phenomenon, embracing various ideologies and affects as groups as lone wolves. It is also multi-located, without boundaries, notably due to the Internet. Since 2005, the European Union decided to elaborate a global approach in order to prevent this phenomenonNonetheless, in democratic systems, the fight against this phenomenon must address the issue
of conciliating opposed objectives: the right to security on one side, individual rights and freedoms, on the other side. Several considered actions and programs may collide with this commitment, firstly because radicalization is inextricably linked with human subjectivity, and secondly because as “preventing” suggests acting before the commission of an offence, it raises the question of up to when/what should it be looked back?