Paris - Two diamonds together worth over 11 million euros ($20.49 million) disappeared from an antique dealers' show in Paris on Monday. Police said a glass case holding the jewels was forced open during the show. One was a white diamond of 47 carats estimated at 6 million euros and the other a blue diamond of 15.74 carats worth 5.5 million. "There was neither any alarm system nor any surveillance camera," a police spokesman said. The diamonds were on show in a hall in the underground shopping arcade at the Louvre, outside the museum's art galleries. Police said the employee of the jewellery firm displaying the diamonds was apparently absent for about 15 minutes, but the manager of the antiques show disputed this. "There was a little incident and a window was forced open at one of the jewellery displays," Christian Deydie told journalists. "There were six people present and all the security was there, it surely happened in a few seconds."