Although the theme of cities at night is growing ever more important on the publicagenda, it seems that no city has emerged as a successful model that could “ circulate,informally, more formally through international or national networks, or very strictly in the formof legislation ” (Roberts & Britain, 2004, p.7). Therefore, City authorities might still have toelaborate innovative models and policies related to the city at night. For want of applicable models, cities and policy makers arrange, invent and experiment best-practices which contribute to what is called in this paper the institution of the urbannight as a public problem (Gusfield, 1984). This paper seeks to understand the modalitiesand the consequences of this process of institution with the city of Geneva as a case study.Like many other European cities, Geneva is facing different issues related to its activity atnight. Some of these issues relate to social conflicts between and opposite demands fromdifferent sets of actors such as the claim by social movements for more spaces andfacilities for independent culture, the increase of cultural and entrepreneurial activitiesand the demands by residents' associations for more quietness at night. Those conflictswere motors of what is described in this paper as a process of institution that has beenfollowed in Geneva during the time of a PhD thesis