Too little objective knowledge is available about violence in primary schools, whereas it is increasingly thought that the phenomenon is reaching down to the primary school level and that "increasingly young authors" are involved. The present research, funded by the Nord/Pas-de-Calais IUFM and the CESDIP, was conducted by a ten members team, from several disciplines (physical training, French, mathematics, philosophy, sociology and education) and several institutions (Nord-Pas-de-Calais IUFM, CNRS, Lille II and Lille III Universities).