More than 300 police officers and two helicopters took part in the collection and search operation. According to preliminary data, the drugs hit the water from an overturned motorboat on 22 March.
READ MORE: Bristol Named 'Cocaine Capital' of Europe Following Release of Sewage Study
Law enforcement officials have called on residents of the nearest town not to open the findings "whose contents could put their lives in danger" and call the police.
In December 2018, French authorities seized 1.6 tonnes of cocaine at the Port of Caen located in the northwest of the country, in another European anti-drugs smuggling operation.