Legislation Requires Green Roofs, Solar Panels

A new law in France requires all new buildings in commercial areas be equipped with green roofs or solar panels.

New legislation in France requires all new buildings in commercial zones to plant vegetation or install solar panels on at least a portion of their rooftop. The green roofs will help reduce energy use by insulating buildings. The vegetation also retains rainwater, which helps prevent runoff , and serves a particularly important purpose in dense cities, such as Paris, of reducing the urban heat island effect. The option to install solar panels instead of green roofs enables companies to generate renewable electricity and will help France advance in the solar market, where it currently lags behind other European countries. Only 2% of France’s electricity use came from solar power in 2013, while in Germany and Spain these figures were 9% and 15%, respectively.<sup>1</sup> The policy is therefore a strong strategic decision to mitigate climate change, while better positioning the country’s renewable energy market.

Relevance of solution

By allowing businesses to choose whether a green roof or solar panels would better suit their needs and preference, the law, while mandatory, provides leniency and offers fl exibility in commercial decision-making towards helping the country’s urban areas mitigate climate change and boost decentralized solar energy generation.

Triple Bottom Line


Green roofs retain rainwater, filter air by absorbing possible pollutants, and reduce energy costs.


As solar panels and green roofs reduce the urban heat island effect,2 the policy will help reduce extreme heat and improve temperature comfort in urban environments.


A green roof can save a building about $200,000 over its lifetime, meaning this new legislation will provide long-term financial benefits to property owners.3


  1. Eurostat. “Renewable Energy Statistics.” (2015.)
  2. Masson V, Bonhomme M, Salagnac J, Briottet X, Lemonsu A. “Solar Panels Reduce Both Global Warming and Urban Heat Island.” Frontiers in Environmental Science (2014.)
  3. Clark C, Adriaens P, Talbot FB. “Green Roof Valuation: A Probabilistic Economic Analysisof Environmental Benefits.” Environmental Science & Technology. (2008.)
  4. Photo © Dominic Alves (Undated.)
  5. Photo © New Brunswick Tourism (Undated.)