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The "new French rule" you're likely hearing about is the significant expansion of the 2021 Climate and Resilience Law, which reaches a major milestone on July 1, 2026.
While France has required "green" roofs on commercial buildings since 2015, the rules have now become much stricter and cover a wider range of buildings, including government and administrative offices.
The 2026 "Solar or Green" Mandate
Starting July 1, 2026, the requirement for rooftops to be "activated" (either with solar panels or vegetation) increases in both scope and percentage:
* Coverage Target: At least 40% of the roof surface must be covered by a renewable energy system (like solar panels) or a greening system (plants/vegetation).
* Note: This target will rise again to 50% on July 1, 2027.
* Building Types Included:
* Public/Administrative buildings (government offices, city halls, etc.).
* Hospitals, schools, and universities.
* Commercial, industrial, and craft buildings.
* Offices and warehouses.
* Threshold: The rule generally applies to new constructions, heavy renovations, or extensions of buildings larger than 500 m² (or 1,000 m² for office buildings).
Key Requirements for These Roofs
The law isn't just about "putting plants on a roof"; it sets specific standards:
* Biodiversity & Insulation: Green roofs must ensure high thermal efficiency (insulation) and promote biodiversity.
* Water Management: They must be designed to capture and manage rainwater, reducing the load on city sewers.
* The "Solar Alternative": The government allows a choice. You can either plant a garden (green roof) or install solar panels. In many cases, "biosolar" roofs—which combine both—are encouraged because plants actually help keep solar panels cool, making them more efficient.
Why the change?
France is pushing these rules to combat the "Urban Heat Island" effect (where cities get significantly hotter than the countryside) and to meet its goal of Carbon Neutrality by 2050.
Gemini