The police source, who wished to remain anonymous, said the men drove a large four-by-four car into the store in the early hours of the morning and grabbed jewellery and luxury watches worth an estimated two million euros.
They then set fire to the vehicle and escaped in another car.
Forensic policemen are currently going through the site of the robbery at the Casty store on Rue de Castiglione in the central first district of Paris, which is home to numerous jewellery shops.
At the end of July, an armed man carried out a brazen robbery in broad daylight at a diamond exhibition at the Carlton hotel in Cannes, making off with jewellery worth 103 million euros in one of the world's biggest ever heists.
Paris has also been the scene of high-profile robberies.
In December 2008, three men emptied almost all of the stock of gems from the Harry Winston jewellery store. In 2009, police said they had recovered 80 percent of the haul.