A mobile phone was used to film passengers for several minutes, who can be heard screaming and calling on God as their plane descends.
The footage contradicts official reports that say the victims were unaware of how desperate their situation was, and only realised in the last seconds.
Banging, which is believed to be pilot Patrick Sondheimer trying to gain access to the cockpit, can also be heard on the video.
Two publications - Germany's Bild and France's Paris Match - appear to have the footage, though they have not yet released it to the public.
The video was allegedly filmed from the back of the doomed Barcelona to Düsseldorf flight, that was deliberately crashed into the Alps last week.
Co-pilot Andreas Lubitz, 28, is thought to have put the plane into a deliberate nosedive when the captain went to the bathroom, also locking him out of the cockpit.
Despite pilot Sondheimer's desperate pleas for him to open the door, and appearing to try and break it down, Lubitz crashed the plane killing all on board.
Lt Col Menichini, in charge of the recovery operation, denied that any footage had been recovered.