The French navy on Thursday intercepted a Russian tanker in the Mediterranean suspected to be part of the so-called shadow fleet, which enables Russia to export oil despite sanctions.
"This operation was carried out ... with the support of several of our allies. It was conducted in full compliance with the United Nations Convention on the Law of the Sea," French President Emmanuel Macron said on X.
The interception was carried out on high seas in the Western Mediterranean, between the southern coast of Spain and the northern coast of Morocco, the French maritime police said in a separate statement.
Navies of other countries, including Britain, supported the operation, the statement added.
EU sanctions on Russia
The EU has imposed 19 packages of sanctions against Russia so far, but Moscow has adapted to most measures and continues to sell millions of barrels of oil to countries such as India and China, typically at discounted prices.
Much of the oil is carried by a so-called shadow fleet of vessels operating outside of the Western maritime industry.
The tanker, named the GRINCH, was sailing from Murmansk in northern Russia and is subject to international sanctions and suspected of operating under a false flag, Macron said in his post.
"The activities of the shadow fleet contribute to financing (Russia's) war of aggression against Ukraine," Macron added.
The case was referred to the prosecutor in Marseille, who handles maritime law matters. It ordered the ship to be diverted for further investigation.
In October, France detained another sanctioned tanker, the Boracay, off its west coast and released it after a few days.