The French government will legislate to require car parks with 80 or more spaces to install solar panels in a move it says could generate up to 11GW of electricity.
The law, which was approved by the senate on Friday, will give owners of car parks with up to 400 spaces five years to comply from July 2023, while owners of bigger car parks will have three years.
The law says at least half the area of the bigger sites must be covered by photovoltaics.
The government is also considering installing solar panels on farmland, and alongside major roads and rail lines. Rail operator SNCF has plans to install more than 1 million sq m of panels between now and 2030, cutting its energy requirement by about 25%.
Politicians had originally applied the bill to car parks larger than 2,500 sq m before deciding to opt for car parking spaces.
As yet, it is not known how the solar panels will be financed, and what form of state aid, if any, will be made available.