Marseille prosecutor Brice Robin, in charge of the criminal inquiry into the crash, told CNN that "so far no videos were used in the crash investigation."
He added, "A person who has such a video needs to immediately give it to the investigators."
Robin's comments follow claims by two publications, German daily Bild and French Paris Match, of a cell phone video showing the harrowing final seconds from on board the flight as it crashed into the French Alps on March 24. Co-pilot Andreas Lubitz is accused of deliberately bringing down the plane, killing all 150 on board.
Paris Match and Bild reported that the video was recovered from a phone at the wreckage site.
The two publications described the supposed video but did not post it on their websites. They said that they watched the video, which was found by a source close to the investigation.
"One can hear cries of 'My God' in several languages," Paris Match reported
. "Metallic banging can also be heard more than three times, perhaps of the pilot trying to open the cockpit door with a heavy object. Towards the end, after a heavy shake, stronger than the others, the screaming intensifies. Then nothing."
"It is a very disturbing scene," said Julian Reichelt, editor-in-chief of Bild online.
An official with France's air accident investigation agency, the BEA, said the agency was not aware of any such video.
Lt. Col. Jean-Marc Menichini, a French Gendarmerie spokesman in charge of communications on rescue efforts around the Germanwings crash site, told CNN that the reports were "completely wrong" and "unwarranted."
Cell phones have been collected at the site, he said, but added that they "hadn't been exploited yet."
Editor 'very confident' clip is real
Menichini said he believed the cell phones would need to be sent to the Criminal Research Institute in Rosny-sous-Bois, near Paris, to be analyzed by specialized technicians working hand in hand with investigators. But none of the cell phones found so far has been sent to the institute, Menichini said.
Asked whether staff involved in the search could have leaked a memory card to the media, Menichini answered with a categorical "no."
Reichelt told CNN's "Erin Burnett: Outfront" that he had watched the video and stood by the report, saying Bild and Paris Match are "very confident" that the clip is real.
He noted that investigators only revealed they'd recovered cell phones from the crash site after Bild and Paris Match published their reports.
"That is something we did not know before. ... Overall we can say many things of the investigation weren't revealed by the investigation at the beginning," he said.
Lufthansa CEO Carsten Spohr expressed his "deep sorrow" Wednesday over the crash of Germanwings Flight 9525 and promised to help the victims' families for as long as they need.
Speaking as he visited the crash site in the French Alps, he said, "There is not a single hour where we don't think about this terrible accident, the victims and the relatives and friends of these victims.
"We are learning more every day about the cause of the accident, but I think it will take a long, long time for everybody, all of us, to understand how this could happen."
Spohr also thanked all those involved in the investigation and recovery efforts as well as local residents for their response to the devastating crash.
He added a wreath to the pile of flowers left by grieving families at a simple stone memorial set up in the village of Le Vernet, the closest accessible point to the crash site.
A memorial service was also to take place Wednesday in the town of Haltern, Germany, which lost 16 students and two teachers in the crash.
Lufthansa confirmed Tuesday that co-pilot Lubitz had battled depression
years before he took the controls of Germanwings Flight 9525.
Lubitz told his Lufthansa flight training school in 2009 that he had a "previous episode of severe depression," the German airline said Tuesday.
Email correspondence between Lubitz and the school discovered in an internal investigation, Lufthansa said, included medical documents he submitted in connection with resuming his flight training.
The announcement indicates that Lufthansa, the parent company of Germanwings, knew of Lubitz's battle with depression, allowed him to continue training and ultimately put him in the cockpit.
Lufthansa, whose CEO Spohr had previously said Lubitz was 100% fit to fly, described its statement Tuesday as a "swift and seamless clarification" and said it was sharing the information and documents -- including training and medical records -- with public prosecutors.
Recovery teams have been working for the past week to recover human remains and plane debris scattered across a steep mountainside.
Menichini told CNN late Tuesday that no visible human remains were left at the site but recovery teams would keep searching.
French President Francois Hollande, speaking Tuesday, said that it should be possible to identify all the victims using DNA analysis by the end of the week, sooner than authorities had previously suggested.
In the meantime, the recovery of the victims' personal belongings will start Wednesday, Menichini said.
Investigative agency chief quizzed
Meanwhile, French investigative newspaper Le Canard Enchaine reported Wednesday that the Gendarmerie Nationale, or National Police, had questioned Remy Jouty, the head of the BEA, regarding leaks in the investigation -- specifically a report in The New York Times about the contents of the cockpit voice recorder.
BEA spokeswoman Martine Del Bono confirmed to CNN that the Gendarmerie Nationale questioned Jouty regarding the Germanwings investigation but refused to elaborate. She said he was questioned on the evening of March 25.
"An investigator said evidence from a cockpit voice recorder indicated one pilot left the cockpit before the plane's descent and was unable to get back in," reporter Nicola Clark wrote.
Wednesday's article in Le Canard Enchainé, citing a government source, said: "They (the Gendarmerie) reproached him (Jouty) for not informing the Prosecutor first regarding the content of the cockpit voice recorder.
"The Marseille prosecutor, Brice Robin, in charge of the investigation and the Gendarmerie found out about the cockpit voice recorder content in ... the press!" said Le Canard Enchainé.
Separately, the French National Union of Airline Pilots confirmed that it had filed a complaint against a person it identified merely as "X" last week for breach of confidentiality after "a source close to the investigation" leaked information to The New York Times.
"The article states that the source is a high official part of the team of investigators and that he had access to audio recordings from the recorder," the union's statement said.
The union said information taken from the recording was "communicated to the press before it was given to the judicial inquiry and especially families." It claimed European rules had been violated by those who had access to the recordings.