The development of smart cities in both mainland China and Hong Kong is a recent phenomenon that take place within a context of environmental and energy transitions and within a context of financiarisation of the city and its services. Therefore, smart cities policies reflect the conditions of the Chinese urban production, characterized by a strong leadership of both the central and local authorities, as well as the establishment of local growth coalitions. This contribution aims to show how digitalisation becomes an important reference frame for local policies in order to examine the real substance beyond staged. For this we propose to confront these public policies to smart (urban) project implementation conditions in mainland China and Hong Kong. Given the shortness of sustainability policies, urban smartness does or does not consist in adding a digital dimension to existing urban projects, desired as sustainable ?