Crisis centre
Mr Borloo, the minister in charge of transport, said the plane would already have run out of fuel.
TIMELINE
Flight AF 447 left Rio at 1900 local time (2200 GMT) on Sunday
Airbus A330-200 carrying 216 passengers and at least 12 crew
Contact lost 0130 GMT
Missed scheduled landing at 1110 local time (0910 GMT) in Paris
Air disasters timeline
"By now it would be beyond its kerosene reserves so unfortunately we must now envisage the most tragic scenario," he said, quoted by Reuters news agency.
"Nothing on Spanish radar, nothing on Moroccan radar, nothing on French radar - we seriously have to fear the worst."
Flight AF 447 left Rio at 1900 local time (2200 GMT) on Sunday. It had 216 passengers and 12 crew on board, including three pilots. The passengers included one infant, seven children, 82 women and 126 men.
An Air France spokeswoman said there had been no radio contact with the plane "for a while".
It is reported to have disappeared 300km (186 miles) north-east of the Brazilian city of Natal.
Brazilian air force spokesman Col Henry Munhoz told Brazilian TV it had not been picked up by radar on the Cape Verde Islands on its way across the Atlantic.
"Air force planes left Fernando de Noronha and are flying towards Europe to start the search for the missing plane," he said.
Airport authorities have set up a crisis centre at Charles de Gaulle.
An Air France official told AFP that people awaiting the flight would be received in a special area at the airport's second terminal.
French President Nicolas Sarkozy has been informed of the incident and has expressed his deep concern, his office said.
He has demanded that the relevant authorities do everything they can to find the plane and "shed light on the circumstances surrounding its disappearance as rapidly as possible".
Air France has opened a telephone hotline for friends and relatives of people on the plane - 00 33 157021055 for callers outside France and 0800 800812 for inside France.
Mr Borloo, the minister in charge of transport, said the plane would already have run out of fuel.
TIMELINE
Flight AF 447 left Rio at 1900 local time (2200 GMT) on Sunday
Airbus A330-200 carrying 216 passengers and at least 12 crew
Contact lost 0130 GMT
Missed scheduled landing at 1110 local time (0910 GMT) in Paris
Air disasters timeline
"By now it would be beyond its kerosene reserves so unfortunately we must now envisage the most tragic scenario," he said, quoted by Reuters news agency.
"Nothing on Spanish radar, nothing on Moroccan radar, nothing on French radar - we seriously have to fear the worst."
Flight AF 447 left Rio at 1900 local time (2200 GMT) on Sunday. It had 216 passengers and 12 crew on board, including three pilots. The passengers included one infant, seven children, 82 women and 126 men.
An Air France spokeswoman said there had been no radio contact with the plane "for a while".
It is reported to have disappeared 300km (186 miles) north-east of the Brazilian city of Natal.
Brazilian air force spokesman Col Henry Munhoz told Brazilian TV it had not been picked up by radar on the Cape Verde Islands on its way across the Atlantic.
"Air force planes left Fernando de Noronha and are flying towards Europe to start the search for the missing plane," he said.
Airport authorities have set up a crisis centre at Charles de Gaulle.
An Air France official told AFP that people awaiting the flight would be received in a special area at the airport's second terminal.
French President Nicolas Sarkozy has been informed of the incident and has expressed his deep concern, his office said.
He has demanded that the relevant authorities do everything they can to find the plane and "shed light on the circumstances surrounding its disappearance as rapidly as possible".
Air France has opened a telephone hotline for friends and relatives of people on the plane - 00 33 157021055 for callers outside France and 0800 800812 for inside France.
