France decrees new roof tops must be partly covered in plants or solar panels.

http://www.theguardian.com/world/2015/mar/20/france-decrees-new-rooftops-must-be-covered-in-plants-or-solar-panels?CMP=share_btn_fb

Rooftops on new buildings built in commercial zones in France must either be partially covered in plants or solar panels, under a law approved on Thursday.

Green roofs have an isolating effect, helping reduce the amount of energy needed to heat a building in winter and cool it in summer.
They also retain rainwater, thus helping reduce problems with runoff, while favouring biodiversity and giving birds a place to nest in the urban jungle, ecologists say.

The law approved by parliament was more limited in scope than initial calls by French environmental activists to make green roofs that cover the entire surface mandatory on all new buildings.