Paris, France — French authorities have detained the captain of the oil tanker Grinch following its interception and seizure by the French Navy in the Mediterranean Sea earlier this week.

The tanker, which departed from the Russian port of Murmansk in early January, was stopped on suspicion of operating under a false flag and being part of a so-called “shadow fleet” used to circumvent Western sanctions on Russian oil exports, according to the Marseille prosecutor’s office.

The 58-year-old captain, an Indian national, was placed into judicial custody on preliminary charges linked to the validity of the vessel’s registration and flag state documentation after the ship was diverted to anchor off the port of Marseille-Fos. Other crew members, who are also Indian nationals, remain aboard the tanker as investigators verify its navigation documents and compliance with international maritime regulations.

French naval forces carried out the high-sea interception on Grinch in the western Mediterranean, between the southern coast of Spain and northern Morocco, last Thursday. The ship was reportedly flying a Comoros flag which authorities say may be a facade at the time of the boarding operation.

This operation marks one of several recent European efforts to enforce sanctions intended to restrict Russia’s revenue from oil sales related to its war in Ukraine, with the vessel’s seizure reflecting growing international pressure on these “shadow fleet” operations.

French President Emmanuel Macron publicly reaffirmed France’s commitment to upholding international law and sanction enforcement following the operation.

The investigation will examine whether Grinch breached maritime law, including potential misuse of flag documentation and compliance with sanctions regimes, as authorities determine next steps in the case.