Traffic congestion, we are told, costs millions each year in wasted fuel and time that could be better spent working. But on one road between Paris and Le Bourget airport, the costs of traffic congestion are spiralling out of control.

Traffic jams on this route are proving the ideal hunting ground for criminals to carry out hold-ups, the latest of which took place today. Two wealthy Qatari sisters were tear-gassed and robbed of items valued at around 5m euros.

Reports say the women were in their sixties and were being driven from the airport by their driver when the holdup took place. Two masked men reportedly held up the Bentley before using the tear gas and taking the valuables.

According to French digital TV station BFMTV there was a chase, after which the car was forced to park at a service station.

Wealthy foreigners are often targeted on the stretch of road in the hope that they are carrying large quantities of cash.

In October the chief executive of a French furniture chain was held up in his taxi after leaving Le Bourget; he was relieved of valuables worth 100,000 euros.

In 2015 4m euros of jewels were stolen from a Korean art collector.

In 2014 a Saudi prince was robbed in his convoy by eight men in two BMWs. They made off with around 315,000 euros and documents of a sensitive nature.

Thankfully, nobody has been seriously hurt in the robberies, but they are no doubt of great concern to Parisian police – not to mention those travelling by car between Le Bourget and the French capital.