How to regulate a Digital Twin City? Insights from a Proactive Law approach: How “human in the loop” and “precautionary principles” can serve policymakers in their attempt to incorporate respect of rights and solidarity in the smart city.

The paper aims to investigate, with a proactive approach to law, some of the core principles at the base of the Digital Twin Cities regulation. To do so, it briefly presents the debate on the inner vision in smart cities projects (and, consequently, also in DTC projects), moving from the ongoing debate between the “City as a Computer” as opposed to the “City as a Living Organism”, to arrive to a more practical approach – for the purposes of this work – formed by the dichotomy “Real-Time DTC” as opposed to “Simulation DTC”. Analyzing those scenarios, the principles of “human in the loop” and “precautionary principle” will be proposed to respond to the “Real-Time DTC” criticality, while also the “Simulation DTC” will be highlighted as a challenge for the lawmaker in its implementation.