In March 2015, the French government passed a law that is set to change the face of France's cities. The law states that the roofs of all new buildings in commercial zones must be covered in part with either plants or solar panels.
The benefits of these so-called rooftop gardens are many. They will help cut the amount of energy needed for heating and cooling the buildings in summer and winter. The plants on green roofs will help filter unpleasant gases, thus cleaning the polluted city air. The soil used to grow the plants will also help retain rainwater. This will make problems with runoff—such as the flooding of sewer systems—a lot rarer. In addition, these rooftop gardens will give birds a place to nest in an otherwise unsuitable city environment. And of course they will create new community areas in cities where space is limited.
French environmentalists wanted the law to state that plants should completely cover the roofs of all new buildings. However, as a first step, the government decided to limit the law's power so that only commercial
buildings would be affected. The government also suggested giving businesses the choice of fitting solar panels onto their roofs to generate their own power rather than growing plants. This would give businesses the chance to cut their own carbon footprints.
France is now one of many countries, including Germany, Australia, and Canada, that use green roofs to lower their negative effect on the environment.
法國政府於2015 年3 月通過一項法律，意欲使法國的城市脫胎換骨。這條法律規定商業區的新建大樓屋頂，必須規劃一部分種植物或裝設太陽能板。