Search aircraft continue to scour the area and the first navy ships are expected to arrive on Wednesday.
The wreckage was spotted about 1,000km off the country's coast and included aircraft seats, an orange buoy, metallic objects and fuel slicks.
Brazilian commercial pilots said earlier on Tuesday that they had spotted what appeared to be fire in the Atlantic.
The Air France flight from Brazil to France with 228 people on board dropped off radar screens on Monday morning, hours after taking off from Rio de Janeiro.
The authorities say they are still trying to determine what caused the accident but think there is no chance of finding survivors.
The airliner had encountered a severe thunderstorm before sending an automated message saying that its electrical system had failed at 02:14 GMT on Monday.
|The first rescue boats are expected to arrive in the area on Wednesday [AFP]
Pierre-Henry Gourgeon, Air France's chief executive, said "several electrical systems had broken down".
"It is probable that it was shortly after these messages that the impact in the Atlantic came," he said.
Jean-Louis Borloo, the French environment minister, said officials did not believe the Airbus A330-200 could have been brought down by something as simple as a bolt of lightning, which previous reports had suggested.
"There really had to be a succession of extraordinary events to be able to explain this situation," he told RTL radio.
He said "the race against the clock has begun" to find the aircraft's two data recorders, commonly known as "black boxes", which emit signals for up to 30 days.
Jobim said the recorders could be on the ocean floor as far down as 3,000m.
Alain Bouillard, who led the probe into the crash of a Concorde in July 2000, has been put in charge of France's accident investigation team.
|The jet was flying from Rio de Janeiro to Paris when it disappeared from radar screens
Herve Morin, France's defence minister, said "we have no signs so far" of terrorism, but all hypotheses must be studied.
Air France said the 216 passengers from 32 countries comprised 126 men, 82 women, seven children and a baby.
There were also 12 French crew members on board.
More than half of the passengers were either French or Brazilian.
If confirmed that all 228 people on board are dead, it would be the worst loss of life in Air France's history and civil aviation's worst accident for more than a decade.