French President Francois Hollande says the case of the second black box has been found, but not its contents.
Speaking alongside German Chancellor Angela Merkel and Spanish Prime Minister Mariano Rajoy, Hollande promised on Wednesday that French investigators would do everything to determine the cause of the crash.
The missing black box was the flight data recorder, which captures 25 hours' worth of information on the position and condition of almost every major part in a plane.
Hollande also said there could be no rescue because it was certain that all 150 people aboard the plane had perished in Tuesday's crash in the southern French Alps.
Meanwhile, the director of France's aviation investigative agency says audio has been recovered from the cockpit recorder salvaged from the crash of the Germanwings plane in the Alps.
Remi Jouty says the material includes sound and voices, and was extracted Wednesday afternoon from the mangled black box recovered from a mountainside.
Jouty says it was too early to draw conclusions from the recording.
Jouty says he couldn't confirm that the case of the second black box had been recovered. (AP)
