The small 20-meter-long fishing vessel saw a French Navy frigate and an amphibious helicopter carrier descend on it.
On Sunday, a major drug seizure was made by French authorities in the Gulf of Guinea.
According to the Maritime Prefecture of the Atlantic, 1.7 tonnes of cocaine was discovered on board the fishing boat.
According to the anti-narcotics office (OFAST), the goods are estimated at more than 50 million euros.
Conducted at the instigation of the prosecutor's office in Brest (Finistère), the mission had started on Saturday May 21 by monitoring the fishing vessel off the coast of West Africa.
A follow-up started following a report from the anti-narcotics office in collaboration with foreign partners and the operational center for the analysis of maritime intelligence for narcotics, based in Lisbon.
The Navy specifies that air and naval resources have been present in the area since the beginning of May "to defend French interests in the Gulf of Guinea, including missions to combat maritime insecurity and illicit trafficking". .
The control of the documents carried out by the sailors of the frigate Courbet "did not make it possible to determine the nationality of the ship", specifies the Prémar.
The boat was declared as "without flag" and was able to be searched by French sailors, who discovered 1,730 kg of cocaine in it.
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