The case could set a legal precedent for corporate environmental advertising, which is starting to face tighter regulations in the European Union.

In Europe, courts ruled against Dutch airline KLM in 2024 and Germany's Lufthansa in March for misleading consumers about their efforts to reduce the environmental impact of flying.

But ClientEarth, an organisation which closely monitors case law against the oil and gas industry, said Thursday's ruling was the first such conviction in the world against an oil company for corporate "greenwashing" -- or the act of claiming to be more environmentally responsible than in reality.

The Paris court found that TotalEnergies had made environmental claims that "misled" consumers into believing that it could achieve carbon neutrality by 2050 while increasing oil and gas production.

The court, however, dismissed complaints over TotalEnergies' fossil gas and biofuels, which activists argued had been deceptively promoted as clean energy.

Greenpeace and two other environment NGOs told AFP the ruling was still "a major legal precedent against climate misinformation".

"This is the first time anywhere in the world that a major oil and gas company has been convicted by the courts for misleading the public by greenwashing its image regarding its contribution to the fight against climate change," said the organisation, one of the plaintiffs in the case.

The civil case stems from a March 2022 lawsuit by three environmental groups accusing TotalEnergies of "misleading commercial practices" for ads saying it could reach carbon neutrality while continuing oil and gas production.

The plaintiffs took that legal route as "greenwashing" is not specifically covered under French law.

Starting in May 2021, TotalEnergies advertised its goal of "net zero by 2050, together with society" and touted gas as "the fossil fuel with the lowest greenhouse gas emissions".

At the time, the company had changed its name from Total to TotalEnergies to emphasise its investments in wind turbines and solar panels for electricity production.

But there was a "big gap" between their advertising which focused on carbon neutrality and clean energy and "their activities which are still mostly based on fossil fuels," said Juliette Renaud from the French chapter of Friends of the Earth activist group, one of the plaintiffs.

The lawsuit targeted around 40 "false advertisements" and requested that TotalEnergies be required to stop using them.

The court agreed, giving the firm one month from officially receiving the ruling to remove ads concerning carbon neutrality and the energy transition, such as: "Our ambition is to be a major player in the energy transition while continuing to meet the public's energy needs."

Another example of claims it must remove is "Our ambition is to contribute to reaching net zero by 2050 together with society."

TotalEnergies's consumer electricity and gas companies in France must also publish the ruling on their sites.