The progressing urbanisation process and its visible effects are prompting local authorities to seek new solutions to contemporary development challenges, especially those identified in post-socialist cities, including in Poland. Nowadays, the smart city concept is becoming widely popular. This idea is grounded in the principles of sustainable development in all spheres of socio-economic life. However, in a comprehensive approach, it moves away from its strictly technological definition towards the social context and local conditions. Nowadays, there are more and more instruments supporting social and civic activity of the inhabitants of Polish cities. One extremely popular mechanism is the participatory budget. In order to trace its importance in the implementation of the smart city concept, an empirical analysis was undertaken in Bydgoszcz (a medium-sized city in Poland). According to the research, the participatory budget is asymmetrical, with infrastructure investments dominating. Support is needed for pro-social activities and those activating residents. Therefore, the diversification of projects in the budget, including setting aside a pool of funds for pro-social and cross-district projects, should be viewed in a positive light.