French police discovered nearly six tonnes of cannabis resin, known as hashish, in a villa in the southern city of Marseille. Cops also arrested three men in connection with the case, the interior ministry said Monday.
The drug bust came after months of investigation and is one of the biggest seizures of cannabis in France in recent years.
Interior Minister Bernard Cazeneuve said in a statement that police had tracked the three men believed to be involved in a vast drug trafficking network to Marseille and the nearby town of Vitrolles on Sunday.
They found 5.6 tonnes of hashish in a villa and another 150 kilos of the drug in a car.
Cazeneuve, who will visit Marseille later Monday, congratulated officers on their "major success".
In 2013, French customs officers seized 7.5 tonnes of cannabis in one day, with 5.5 tonnes found in a truck carrying courgettes and another two tonnes in a truck carrying oranges.
The biggest ever cannabis seizure in France was in 1999 when 23.5 tonnes was seized in one haul.