The French navy seized nearly 10 tons of cocaine on Monday from a fishing boat sailing off the coast of West Africa, whose crew will be handed over to French justice, the Atlantic maritime prefecture and the Brest prosecutor's office announced Thursday.

"It's a success, a fairly unprecedented catch," said Vice-Admiral Jean-François Quérat, Maritime Prefect of the Atlantic, during a press conference in Brest.

Teams from two French Navy ships intervened Monday morning as part of the Corymbe naval mission, a deployment through which France ensures its presence in West Africa and the Gulf of Guinea.

In total, 9.6 tonnes of cocaine, with an estimated street value of nearly 519 million euros, were seized, according to the maritime prefecture.

This wooden fishing vessel, about twenty meters long, had no flag (that is, it was not registered in any state). It was sunk at the end of the intervention.

The six crew members were placed under "restrictive measures involving deprivation of liberty" and will be transported by the French Navy to the specialized interregional jurisdiction (Jirs) in Fort-de-France (Martinique), where they face "at least 20 years" in prison, said Brest prosecutor Stéphane Kellenberger, welcoming "fruitful and smooth cooperation with the French Navy."

In such operations off the African coast, the ship is usually left free to resume its course.

"The French Navy's vessels are now organized to accommodate traffickers. In this case, the boat that intervened was able to ensure this detention," said Mr. Quérat, who declined to disclose the nationality of the crew.

"The ship was probably in transit to Europe," he said only.

An automatic weapon and ammunition were found on board. The seized drugs were destroyed after sampling.

By the end of August, the French navy had already seized nearly six tons of cocaine off the coast of West Africa.

Since the beginning of the year, the French navy has seized 54 tonnes of cocaine in the Atlantic and Pacific, compared to 47 tonnes last year and 20.2 tonnes in 2022, according to the maritime prefect.

"This means that there is probably an increase in production and therefore in the flow to the African continent and more likely to Europe," Mr. Quérat pointed out.