It is the first such case in France targeting a major energy company and could set a legal precedent for corporate environmental advertising, which is starting to face tighter regulations in the European Union.

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" -- or the act of claiming to be more environmentally responsible than in reality -- 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.

"It's misleading, there is a big gap between reality and their activities which are still mostly based on fossil fuels... and their advertising which focuses on carbon neutrality and promoting gas and biofuels as clean energy," said Juliette Renaud from the French chapter of Friends of the Earth activist group.

The lawsuit targeted around 40 "false advertisements", some of which are still being used, according to climate groups.

It requested the court order their use be halted and TotalEnergy be required to put disclaimers on its ads that include warnings about the impact of fossil fuels on the climate.

- Possible precedent -

"For the average consumer, it is impossible to understand that TotalEnergies is actually expanding fossil fuel production," Clementine Baldon, a lawyer for the NGOs, said at a hearing in June.

TotalEnergies maintains it has not engaged in misleading commercial practices and that it is "simplistic" to immediately stop using fossil fuels.

TotalEnergies also insisted that the messages are part of its institutional communications regulated by financial authorities and not consumer law.

It argued that the ads did not target consumers but its stakeholders such as investors and clients.

The affair was an exploitation "of consumer protection laws to criticise the strategy of the group", TotalEnergies told AFP.

Companies have talked about their environmental commitments in ads for years, often resorting to vague terms such as "green" and "sustainable".

But the legal terrain surrounding such claims is beginning to emerge.

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.

A ruling against TotalEnergies "would put the oil and gas industry on notice that claiming to be aiming for net zero by 2050 when expanding fossil fuel production, or promoting gas as a climate solution, is misleading," said Johnny White, a lawyer with ClientEarth.

"The case will set the precedent for oil and gas industry advertising narratives in EU consumer protection law" and even elsewhere as such laws are generally very similar, he added.

But legal rulings have not always gone against energy companies that are making environmental claims.

In Spain in February, utility Iberdrola Energia lost a case it had brought against Spanish oil and gas company Repsol over similar environmental claims.