France is to conduct air, land and sea searches in and around the island of Reunion in the hope of finding more debris which could be linked to MH370.
Malaysia said on Thursday that a wing section found on the French Indian Ocean island definitely came from the doomed Malaysia Airline flight.
But investigators in France are yet to confirm the link, causing frustration among the families of victims.
France has also dismissed Malaysian claims that more debris has been found.
The Boeing 777 was travelling from Kuala Lumpur to Beijing on 8 March 2014 when it vanished from radar. It had 239 people on board, most of them Chinese.
For a third day, relatives angered by mixed messages from the authorities are staging a small protest outside Malaysia Airlines’ offices in Beijing.
The BBC’s John Sudworth, who is at the protest, says many are refusing to accept Malaysia’s confirmation.
‘Shed light on this tragedy’
The French government said in a statement that a military Casa aircraft would begin surveying the area around Reunion on Friday morning, along with helicopter and boat patrols and search teams on foot.
Saying it recognised the pain for the families, the statement (in French) said France would play its full part in international efforts to “shed light on this tragedy”.
The wing section found on Reunion, known as a flaperon, is being examined in the French city of Toulouse by international aviation experts.
Malaysian Transport Minister Liow Tiong Lai said paint and “many other technical details” on the flaperon tallied with MH370’s maintenance records.
Window panes and seat cushions had also been found near Reunion which were yet to be identified, he said.
French officials, however, have said no other debris has been recovered, and have only said there is a strong possibility that the flaperon came from MH370.
Mr Liow said he understood why the French team had been less categorical in their conclusions over the flaperon, saying: “We respect their decision to continue with their verification.”
Relatives of those on board have long been frustrated by Malaysia’s handling of the disaster, which at times has been marred by contradictory and conflicting information.
The lack of a consistent message on the debris has further angered them.
“France is being cautious about it, but Malaysia is desperate to put an end to this case and run away from all responsibilities,” Dai Shuqin, sister of one of the passengers, said on Thursday.
“We suspect that the plane wreckage could be faked,” said Liu Kun, whose younger brother was on the plane.
China’s foreign ministry said Malaysia must keep investigating the crash and “safeguard the legitimate rights and interests” of relatives.
The Australian Transport Safety Bureau (ATSB) has been co-ordinating the deep-sea hunt in the southern Indian Ocean, where the plane is believed to have gone down, thousands of miles east of Reunion.
Prime Minister Tony Abbott said that search would continue as “we owe it to the hundreds of millions of people who use our skies”.