Designed by art students Audrey Charré, Clémentine Schmidt and Luc Beaussart, the 'Urban Greenhouse' wants to show and give value to the plants which grow by themselves in a city. Those discredit plants are, in fact, healthy, médicinal and sometimes eatable. The first part of the project was to give value by a three-dimensional graphic intervention. The other part of the project was to use those plants like a kind of material to make leaf mould. The organic waste become a strong productive material. The relevance of this project is to see what is already here in the city, to find a purpose to create a cycle from the city.