The debris, part of a plane wing, could provide the first tangible clue towards unlocking the mystery surrounding the Malaysia Airlines plane, which disappeared in March last year with 239 people on board.
"I believe that we are moving closer to solving the mystery of MH370. This could be the convincing evidence that MH370 went down in the Indian Ocean," Malaysia's deputy transport minister Abdul Aziz Kaprawi told AFP.
However, authorities have warned one small piece of plane debris was unlikely to completely clear up one of aviation's greatest puzzles.
(A helicopter flies along the coast as officials look for more clues. Photo: AFP)
The Malaysia Airlines flight was one of only three Boeing 777s to have been involved in major incidents, along with the downing of the MH17 over Ukraine last year and the Asiana Airlines crash at San Francisco airport in 2013 that left three dead.
The wing component found on the French island of La Reunion bears the part number "657 BB", according to photos of the debris.
"From the part number, it is confirmed that it is from a Boeing 777 aircraft. This information is from MAS (Malaysia Airlines). They have informed me," the minister told AFP.
(The wreckage on the island of Réunion. Photo: BFM TV/screengrab)
Martin Dolan, chief commissioner of the Australian Transport Safety Bureau, which is leading the MH370 search, said greater clarity on the origin of the part should be confirmed "within the next 24 hours".
"We are increasingly confident that this debris is from MH370," Dolan told AFP.
Abdul Aziz said a team of Malaysian investigators had arrived in Paris where the wreckage is due to arrive Saturday at 06:20am (0420 GMT) before heading to the city of Toulouse.
(A closer look at the "flaperon" on a Boeing 777. Photo: WikiCommons)
The debris will be analysed "next week", according to a source in the French investigations team.
Main debris at bottom of ocean
Scientists say there are several plausible scenarios in which ocean currents could have carried a piece of debris from the plane to the island.
Australian Deputy Prime Minister Warren Truss said while the part "could be a very important piece of evidence" if it was linked to MH370, using reverse modelling to determine more precisely where the debris may have drifted from was "almost impossible".
Australian search authorities, which are leading the hunt for the Boeing 777 aircraft in the Indian Ocean some 4,000 kilometres (2,500 miles) from La Reunion, said they were confident the main debris field was in the current search area.
Dolan said the discovery of the debris, which experts said could be a flaperon from a Boeing 777 aircraft, did not mean other parts would start
washing up on La Reunion.
"Over the last 16 or 17 months, any floating debris would have dispersed quite markedly across the Indian Ocean," he said.
Truss said accident investigators would be keen to examine the part to try to find out how it may have separated from the rest of the jet and "whether there's any evidence of fire or other misadventure on the aircraft."
But Dolan cautioned it would be difficult to determine why the plane disappeared from the debris.
(Officials transport the debris. Photo: AFP)