Cities, where 60% of the world’s population lives, are particularly vulnerable to global warming. The environmental aspect is therefore an important dimension of sustainable smart cities, as is citizen participation. Based on the Value–Belief–Norm (VBN) theory, we explore the idea that citizen participation in the smart city is largely conditioned by the environmental consequences and responsibilities they attribute to their behaviour. A survey was conducted among 1670 residents of six major French cities involved in a smart city approach. Based on a model test using the PLS-PM approach, the results, confirm the validity of VBN theory in the French smart city context. More specifically, pro-environmental personal norms positively influence residents’ intention to participate in the smart city. Biospheric and altruistic values promote an ecological vision of the world, which strengthens awareness of environmental consequences and a sense of responsibility, which in turn activates pro-environmental personal norms. In this way, we demonstrate the relevance of mobilising the VBN theory to understand citizen participation in the smart city. Citizen participation in the smart city is ultimately a pro-environmental behaviour in itself. We make suggestions on how to develop citizen participation by strengthening environmental awareness and responsibility.