Officials found the drugs, concealed in sports bags stashed in several containers on board the vessel, in several stages over the course of the last two months.
The latest discovery on the boat came on Saturday, when nearly half a tonne was found, prosecutor Francois Gosselin told reporters.
Eight men from the Le Havre region have been charged, six of whom are being held in custody.
Earlier this week the French navy netted another big cocaine haul in the Pacific, seizing 1.46 tonnes of the drug bound for Australia hidden in the hull of a yacht.
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