"We are dealing with organised networks who are slowly destroying African elephants," said Helene Crocquevieille, director general of the customs agency.
The ivory was seized in two separate cases.
Customs agents were alerted to one network when, during a road transport check in September, they discovered four elephant tusks in a car.
Investigations led them to a French-Vietnamese businessman in Paris who had 212 kg of tusks hidden in wooden pallets in his office, which agents discovered on May 25.
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"He used this to organise the trafficking of ivory," said Gutermann.
A dew days later, on June 1, customs agents at Paris' Charles de Gaulle airport said they intercepted a man on his way from Angola to Vietnam who was carrying 26 elephant tusks, weighing 142 kg, in his luggage.
The passenger was sentenced to 18 months in prison and handed a USd 160,000 fine.
The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) banned the ivory trade in 1989.