"It's still a jigsaw puzzle," said Alain Bouillard, who will be in charge of the recovery operation. "We do not know where the recorders might be."
Kosciusko-Morizet said she was hopeful the flight data recorder, sometimes called the black box, would be found.
"The fact that we found various pieces, a lot of pieces of the plane in a quite concentrated area is a good hope for finding the black boxes, but we have no assurance," she said.
It is impossible to tell how many bodies remain in the wreck, he added. Fifty bodies were recovered in previous searches, leaving 178 victims still missing.
He would not comment on the condition of the bodies, calling it "inappropriate" to discuss.
The debris is dispersed over "quite a compact area" of about 600 meters by 200 meters (1,960 feet by about 650 feet), he said.
All the wreckage will be brought to the surface and sent to France for study, said Jean-Paul Troadec, head of the French air accident investigation agency, the Bureau d'Enquêtes et d'Analyses, or BEA.
"We want to know what happened in this accident, most particularly so it never happens again," he said.
Three companies bidding to raise the wreck have until Thursday afternoon to submit proposals, he said.
The operation should take three weeks to a month, and will be paid for by the French government at an estimated cost of 5 million euros ($7.1 million), he said.
Authorities are not revealing the exact location of the wreck to protect the site, officials said.
The head of Air France said the discovery was "good news indeed since it gives hope that information on the causes of the accident, so far unresolved, will be found."
Air France's Pierre-Henri Gourgeon added his thanks to the French authorities "who employed hitherto unheard of means to pursue searches."
