Le Monde newspaper reported on Wednesday that Total Energies was involved in supplying gas condensate to make jet fuel that might have been used by Russian warplanes in Ukraine, via the French firm's stake in a venture with Russia's Novatek .

Clement Beaune, who said he did not have enough information to take sides on the matter, was the first French government official to comment on the allegations which could undermine President Emmanuel Macron's efforts to push for peace in Ukraine.

"This is an extremely serious subject, so it needs to be verified whether, voluntarily or involuntarily, there has been a bypass of either the sanctions or the energy that a company, French or other, has produced," Beaune told France 2 television.

He did not say whether a formal investigation was needed.

Manon Aubry, a member of the European Parliament for France Unbowed, one of the main French opposition parties, urged the government on Thursday to take a stance on the issue, saying that "France can't close its eyes any longer".

"We have a French company that has become an indirect accomplice in a murderous war," she told Franceinfo radio.

Total Energies, which unlike major Western rivals has held on to its assets in Russia despite criticism, said it did not operate infrastructure that would have supplied the Russian military and had no knowledge about any potential jet fuel production by its business partners.

Le Monde said the jet fuel delivered to two Russian air force bases which likely were involved in carrying out air strikes in Ukraine was produced from gas condensate supplied by Terneftegaz, in which Total Energies holds 49%.