Paris has set up the participatory budgeting scheme, ‘Madame Mayor, I have an idea’, which will allocate €500 million to projects proposed by citizens between 2014 and 2020, and claims to be the largest exercise of its kind in the world.

The most popular proposals so far, with more than 21,000 votes, is an idea to develop 41 vertical garden projects across the city (one of which is pictured here). The city has committed to investing €2 million in these projects. Other popular projects include setting up recycling stations, gardens in schools and co-working spaces for students and entrepreneurs.

The pilot phase of the campaign, launched in 2014, received over 5,000 proposals. While votes and proposals could only be submitted online, the campaign also organised physical meetings across the city to ensure older people weren’t left out.

Budgets for the project have been divided among the 20 districts in Paris based on economic need, with the poorer, outer suburbs allocated 15 times the amount put aside for central Paris.