A co-city should be based on collaborative governance of the commons whereby urban, environmental, cultural, knowledge and digital commons are co-managed by the five actors of the collaborative/polycentric governance—social innovators (i.e. active citizens, makers, digital innovators, urban regenerators, rurban innovators, etc.), public authorities, businesses, civil society organizations, knowledge institutions (i.e. schools, universities, cultural academies, etc.)—through an institutionalized public-private-citizen partnership. This partnership will give birth to a local peer-to-peer physical, digital and institutional platform with three main aims: living together (collaborative services), growing together (co-ventures), making together (co-production).