Taking in account the difficulties to define what is an urban common, this proposal wishes to focus on the relations between commoning processes and urban regeneration. In the last few years we can see emerging different experimental public policies and urban transformation processes that aim not only to give citizens the possibility to manage public properties in a common interest, but also to encourage private groups to take charge of the architectural transformation of public buildings. This proposal will be focused on the extents and limits of the comparison between two European countries, Italy and France, more precisely between the cities of Turin, Bologna and Grenoble. In the three cities we find similar case studies in terms of actors, stakes and urban impacts. To enquire on those similarities and differences needs to reflect on a methodology that can question the production of discourses, spaces, knowledge and values related to commoning processes. Those topics allow us to question not only the impacts of commons on city governance, but also on how spaces are reshaped and redesigned.