The project provides an innovative process and tools for empowering the multiplicative imagination of public spaces and streets, leading to actual urban interventions towards sustainability. Car parking spaces, public transport stops and mobility hubs, waste and reuse collection containers, package exchange stations, decentralised public offices are reshaped in the use-cases (embedding the 15-minutes-city goals) of a bottom-up process (involving experts, citizens, private companies, researchers, NGOs and city authorities). Covering from visualisation to evaluation, funding and execution, this process is codified for transferability. Basic and advanced services are co-designed in Living Labs and localised in critical areas by a participatory process embedding a proven open-access visualisation tool of the built and non-built environment, multiplied by a marketplace of innovative solutions and a crowdfunding platform. Citizens’ proposals can be budgeted. The cities select what to implement, keeping into account this "participatory urbanism" and all constraints (zero emission and other goals, laws, stakeholder interests, ownership rights, etc.). Cities can co-finance the investment, look for private investors, or draw on crowdfunding campaigns. In other terms, we are setting up a replicable movement of constant improvements of the urban landscape by fostering the multiplicative involvement of all actors