A submarine scouring the Indian Ocean on Sunday detected the signal beacons of the two black boxes from a Yemenia Airways flight that crashed off the Comoros Islands, the French aviation agency said.
Plans were under way to retrieve the boxes within days, an official from Yemen said.
A 12-year-old girl, Bahia Bakari, who clung to debris for up to 13 hours, is the only known survivor of Tuesday's crash, which killed 152 people flying from Paris to Moroni, the capital of the Comoros, via San'a in Yemen.
The chief of Yemen's Civil Aviation Authority, Hamed Ahmad Faraj, had only grim news Sunday for reporters, saying that search planes have spotted another floating body.
The Airbus A310's flight data and cockpit recorders inside the black boxes are critical to help investigators understand why the flight went down, but the one-line statement from the French investigation agency BEA gave no indication when they might be recovered.
However, Mohammed Abdel-Rahman, spokesman for Yemen's Supreme Committee on Civil Aviation Accidents, said search teams were working on plans to retrieve the black boxes within the next few days. Faraj said the French were bringing in special equipment from Djibouti to help.
French defense officials in Paris had no immediate comment.
A team of Yemeni divers left Sunday for Moroni, the Comoros' capital. French navy divers also were on the scene. Earlier, Yemeni officials said divers have recovered some pieces of the plane's fuselage.
Yemenia Flight 626 crashed while preparing to land off the northern end of the main island of Comoros, an archipelago of three main islands 1,800 miles (2,900 kilometers) south of Yemen, between Africa's southeastern coast and the island of Madagascar. Heavy winds were reported at the time of the accident.
Faraj said communications between the Moroni airport tower and the plane's pilot did not contain any hint that the plane was in trouble.
Critics within France's Comoran community have claimed that safety lapses may had doomed the aircraft. Protesters have picketed the airport, prompting Yemenia to announce it was suspending all flights from Marseille to Moroni for an indefinite period. Two weekend protests against the airline have drawn thousands in France.
"We no longer want to take Yemenia home. That's definite," said Ahmed Badudjin, who marched Sunday in Paris to honor victims and protest the conditions of Yemenia planes.
Police said 5,000 people protested in Paris, a day after at least 10,000 marched in Marseille. Critics claim the airline uses planes in good condition for Europe but ones with safety lapses for the leg between San'a and Moroni.
The BEA agency and Airbus have sent teams of experts to Comoros to investigate the crash, and French and U.S. ships are running a search mission, looking for bodies and debris.
The crash was the second major air disaster in a month, following the June 1 crash of the Air France Airbus A330 in the Atlantic Ocean while en route from Rio de Janeiro to Paris, killing 228 people. The black boxes on that aircraft have not been found, but teams are scheduled to comb the Atlantic until July 10.