A French Navy Caiman helicopter crashed just seconds after taking off from the flight deck of the Mistral-class amphibious assault ship Dixmude at 22:29 local time on Wednesday, October 17.
The incident occurred in the North Sea about 130 kilometres from Dunkirk.
The aircrew were able to escape unharmed from the helicopter, but four sailors working on Dixmude's flight deck were injured in the crash, one of them seriously.
The seriously injured sailor was quickly airlifted to the military hospital in Percy in the Normandy region, where he is being treated.
Investigations to determine the causes of the incident have begun.
