This paper examines the growing tension between urban and global dimensions in democratic participation and constitutionalism. As global constitutionalism evolves beyond national and even transnational boundaries toward a cosmopolitan framework, it simultaneously confronts the need for local legitimacy, particularly within urban contexts where democratic engagement is most tangible. Cities and regions emerge as key epistemic arenas where participatory practices can bridge the gap between localized democratic needs and universal constitutional ideals. Post-national constitutionalism thus entails both an external shift toward global governance and an internal redefinition of constitutional norms within urban political spaces. By positioning the city at the center of a deliberative constitutionalist framework, this paper analyses a pathway to reconcile abstract global values with practical urban democratic legitimacy.