Two diamond dealers were attacked with tear gas at a Paris Metro station and robbed of a briefcase filled with precious jewels worth around €300,000.

The dealers, both from India, were caught up in the Hollywood-style heist as they were about to pass through the turnstiles at Cadet Metro station in the 9th arrondissement in the French capital.

But the businessmen were attacked by two robbers who sprayed them with tear gas, and after a brief struggle made off with the case full of precious gems.

The attack took place on Monday (26 February) at 4pm in the afternoon.

Police are working on the notion that the attackers were well-informed about the movements of the two dealers, according to French newspaper Le Point.

Earlier in the day the dealers had travelled to an address in the neighbouring 10th arrondissement to strike a deal for the jewels. However, the sale did not go through and the men were returning to their hotels, when they were targeted by the robbers.

"The two traders were coming back from a business meeting and were attacked Monday afternoon by two men," a source told French news agency AFP.

The source added: "A bag containing several precious stones -- but no diamonds -- was stolen. Early indications are that it could have been a premeditated attack."

In January, a high-class jewellers at the Ritz Hotel in Paris was robbed of €4m in precious stones in an audacious smash-and-garb raid.

Five men armed with axes and handguns burst into the shop at around 6.30pm on 11 January and smashed display cases and grabbed gems before fleeing on mopeds.

They were chased by police who managed to arrest three of the gang, but the remaining two managed to get away.