The “enclosure of the commons” is a popular topic in political economics and philosophy of law. Discussions about open source and creative commons are just two examples that come to mind. In this seminar, we will attempt to describe what exactly it is that constitutes these “commons” for an urban context. What are the commons of a city and how can artists contribute to these commons with artistic interventions in public spaces? Or better, how do they generate public space by artistic interventions? And, how do they generate common ground and infrastructures by their actions? Which strategies do they follow, and to what (legal, political, economical) limits do they run? How do they deal with authorities, and authorities with them? This ARIA research seminar has the honor to present a distinct international group of visual artists, architects, authors, theater directors, performers, lawyers, journalists, curators and researchers who deal with this liminal civil zone between creativity and criminality. Here, I had the honor to be the moderator of one of its round panel discussion.