Two Qatari women were held up with their driver on a Paris motorway and robbed of valuables worth "at least five million euros ($5.3 million)", police sources said on Tuesday.
The women, who are in their sixties, had just left Le Bourget airport northeast of the capital on Monday when their Bentley was held up by two masked men, who sprayed them with tear gas and stole "everything in the vehicle: jewels, clothes, luggage", one source said.
The portion of motorway leading north from Paris to the Charles de Gaulle and Le Bourget airports is often the scene of hold-ups targeting wealthy foreigners in luxury cars, some of whom carry large amounts of cash.
The robbers often take advantage of traffic jams to pounce.
Last month, a taxi transporting the CEO of a French furniture chain among other passengers was held up after leaving Le Bourget.
The three robbers made off with an estimated 100,000 euros in valuables.
A Korean art collector was the target of a similar heist last year, with three attackers snatching four million euros in jewels from her car.
Within Paris itself a number of high-profile robberies have led the government to step up security around tourist spots.
In October, American reality TV star Kim Kardashian was tied up and robbed at gunpoint of $10 million in jewels in a luxury apartment in the heart of the city.