After providing an overview of the changes in the European and domestic economic constitution, the article discusses how contracts are being functionally adapted for environmental purposes, particularly focusing on public contracts and minimum environmental criteria. It also reflects on their potential to act as a tool for shared administration, despite facing some critical issues related to the principle of horizontal subsidiarity. More specifically, there is increasingly pervasive intervention by public authorities, capable of overcoming the current differentiation between command and control instruments and market instruments, but requiring a delicate balance between freedom of economic initiative and environmental interests, as well as adequate awareness and proportionality of administrative action.