A French rule targeting ESG funds has the potential to force oil and gas divestments of €7 billion ($7.6 billion), according to an analysis by Morningstar Inc.

“This revamp is a significant indicator of the mood of one of the strongest ESG markets in the world,” said Hortense Bioy, global director of ESG research at Morningstar which conducted the analysis.

France said earlier this month it will only let funds use a national ESG label if they blacklist fossil-fuel companies that are still expanding production. The label, known as SRI, is currently being used by funds managing a total of €770 billion in client assets. Morningstar estimates the new rule will affect 45% of these.