The smart city concept has existed for decades now. It was presented as a response to help cities cope with challenges they were facing such as rapid urbanization, climate change, resource depletion, and sustainability. Based mainly on sensors, flow optimization and algorithms, this model has revealed its limits. In smart city endeavors, citizens are seldom included in the planning process, although they hold a central position to produce and share useful knowledge on how they live and use the city. Technology has already been exploited to enhance city management, but it is still widely underused in urban planning even though it holds great promise. It has the potential to create tools that improve interaction between urban planners and city dwellers, which is a key aspect for more sustainable and responsive planning. This study explores how digital technologies can be harnessed to generate new ways of involving citizens in city planning, using the data they produce. Digital tools are changing the whole practice of urban planning by adding a non-expert but practiced knowledge layer in the planning process towards more sustainable cities.