Why and how do norms emerge? Which norms emerge and why these ones in particular? Such questions belong to the ‘problem of the emergence of norms’, which consists of an inquiry into the production of norms in social collectives. I address this question through the ethnographic study of the emergence of ‘norms against violence’ in the political collective Occupy Geneva. I do this, first, empirically, with the analysis of my field observations; and, second, theoretically, by discussing my findings. In consequence (...) of two episodes categorized as sexual assaults that occurred in their camp, the members of Occupy Geneva decided to tackle those issues in a general assembly. Their goal was to amend their first charter of good conduct in order to reform its norms and complete it with norms aiming to regulate ‘facts’ of ‘unjustified violence’. During a collective deliberation, new norms were devised, debated and consensually adopted. The writing of the new charter took place in a second general assembly during which the wording of the written norms was collectively decided. I show that indignation over the sexual assaults was the main motive that led to the collective deliberation, and that the entire process of the making of these norms was characterized by different collective emotions. Indeed, indignation, contempt and fear played major roles in the emergence of norms prohibiting violence, allowing punishment and exclusion of wrongdoers, and prescribing collective intervention against an aggressor to neutralize the threat represented. These findings prompt me to hypothesize that social norms emerge from emotions thanks to the latters’ internal structure; and that emotions provide causal and grounding explanations for this emergence. Thus, emotions allow us to answer the questions: ‘Why do norms emerge?’ and ‘Why do they have their specific forms?’ In short, I argue that social norms have emotional foundations. (shrink)