Environmental groups in France had called for a more stringent version of the law, one which would have required new commercial construction to have complete green roof coverage. Instead, lawmakers opted to give developers the option of topping buildings with either partial green roofs or solar panels.
It is well known that green roofs help to absorb rainwater and reduce runoff while providing green spaces in otherwise developed, urban areas. Green roofs also play a significant role in reducing urban “heat island” effect which sees built up areas running warmer overall than other more widely spread centres.
The option provided by lawmakers to install solar panels rather than green roofs may also help France catch up in terms of adoption of solar energy. Think Progress reports that France had only five gigawatts of photovoltaics installed as of last summer, accounting for one percent of all energy production.