C-Tech project aims at researching, developing and pilot-scale a digital smart city platform for urban modelling and planning which, based on a three-dimensional representation of the city and its combination with multiple data from different data sources (from domains such as weather, energy and water consumption, mobility and, most of all, user’s behaviour as determined by their mobile phone use), will allow simulating scenarios regarding energy-efficiency of buildings, green structures, creation and urban mobility, empowering local authorities to identify and tackle specific environmental issues, overcome the global challenge of decreasing urban carbon footprint and fostering the transition to a net-zero ecosystem.