Paris just passed a new law that allows anyone to plant an urban garden within the city’s limits. Upon receiving a permit, gardeners can grow plants on walls, in boxes, on rooftops, under trees, or on fences. They can cultivate greenery in front of their homes or offices. They can grow flowers, vegetables, and fruit. Paris mayor Anne Hidalgo’s goal is to create 100 hectares of living walls and green roofs by the year 2020,…