The video also shows what appears to be part of the aircraft hitting the mountains, according to Bild.
The publications said no individuals could be made out and it was unclear whether it had been filmed by a crew member or a passenger.
Lufthansa said it was aware of reports about the footage but questioned whether a mobile phone could have withstood the impact.
"We have not seen the video and we do not know if it exists," a spokesman for the company said. "Therefore we cannot confirm if the video is genuine.
"Considering that everything on the plane was destroyed, it would be unusual for a mobile phone to survive the impact."
Lieutenant Colonel Jean-Marc Menichini, a high-ranking official involved in the recovery operation, has denied that any mobile phone footage had been found by investigators at the site.
Lufthansa, Germanwings' parent company, admitted Lubitz had told the airline's flight training school he suffered a serious episode of depression in 2009, citing emails between the pilot and the flight school.
German prosecutors said on Tuesday that Lubitz's medical files show he underwent a prolonged course of therapy for "suicidal tendencies" before getting his pilot's licence. Lufthansa did not comment on his suicidal tendencies yesterday, but has previously said that German confidentiality rules meant the company had no knowledge of Lubitz's medical records.
Lufthansa is facing unlimited liability for damages in the crash, lawyers have said, and has told its insurers to set aside US$300 million to deal with claims, recovery costs and the loss of the aircraft, nearly twice as much as insurers would usually pay out over an air accident.
- Independent, PA