Five men smashed the windows during the raid which took place around 6.30pm local time. Three of the raiders were soon arrested by police, but two of the gang escaped through a back door.
The hotel is located beside the French Justice Ministry which is guarded by armed soldiers around the clock.
The gang smashed their way into reinforced glass cases which held the jewels. Witnesses drinking in the Hemingway Bar said they heard gunshots from a handgun during the dramatic raid.
Local radio station RTL said three of the raiders were arrested at the scene.