City digital twins and the urban laboratory: The practice and politics of ‘sandbox urbanism’

City Digital Twins (CDTs) are digital platforms that combine urban data to support city monitoring through predictive simulations and the visualization of city dynamics. Through case studies of Rennes Métropole, the Communauté d'agglomération Paris-Saclay, and Dassault Systèmes—two French intermunicipal authorities and a global software firm—this paper conceptualizes CDTs as “urban laboratory projects” that aim to performatively enact cities as sites for technological innovation. Yet, as entrepreneurial actors use CDTs to showcase innovative self-narratives, advancing these projects locally requires the negotiated ‘enrolment’ of various organizational partners. In these interactions, entrepreneurs flexibilize the definitions of their projects in order to adaptat to institutional obduracy. This is found to be a recursive cycle in which flexibility and stability in the organization of urban networks are self-reinforcing. While urban laboratory projects like the CDT may support the advancement of a certain 'innovative' symbolic order, the interaction between (1) flexible project definitions and experimental relationships on the one hand and (2) stable institutions and sustained narratives on the other often produces ephemeral experiences over lasting infrastructural or institutional change. The study finds that the enactment of the urban laboratory reinforces a “sandbox” approach to urban governance in which projects are constantly renewed but never completed. Through a discussion of this ‘sandbox urbanism,’ the research offers a critical view of the social entropy generated by the laboratorization of urban governance.