Three men pretending to be customers stole a 250,000 euro ($347,000) diamond ring from the Tiffany & Co concession in the Printemps department store in central Paris on Thursday, police in the French capital said.

The three men asked to look at several expensive rings, deciding on a three-carat diamond set in a platinum ring.

They requested a copy of the certificate of authenticity for the diamond ring and when the salesperson went off to make a photocopy they escaped with the ring and managed to avoid being caught by Printemp's security guards.

The store’s surveillance video is being examined for clues as to the identity of the thieves, police said.