If confirmed as being from the doomed Malaysia Airlines flight, the discovery would mark the first breakthrough in a case that has baffled aviation experts for 16 months.
The convoy containing the two-metre wing part was escorted by police overland from Paris to the defence ministry laboratory near the southwestern city of Toulouse, encased in a wooden crate.
The part, identified as a flaperon, was flown overnight to the mainland from the French island of La Reunion, where it was found on a beach in the town of Saint Andre earlier this week.
MH370 disappeared on March 8, 2014, en route from Kuala Lumpur to Beijing with 239 people on board.
Malaysian and French experts will begin their analysis of the part on Wednesday, as well as fragments of a suitcase discovered nearby, according to an informed source.
Today, a few hundred people attended a mass in Saint Andre in remembrance of the victims, a few hundred metres from the spot where the flaperon was found on Wednesday.
"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.
Some warn that one small piece of plane debris is unlikely to completely clear up one of aviation's greatest puzzles.
Australian Deputy Prime Minister Warren Truss said while the part "could be a very important piece of evidence", using reverse modelling to determine more precisely where the debris may have drifted from was "almost impossible".
MH370 was one of only three Boeing 777s to have been involved in major incidents, along with the downing of flight MH17 over Ukraine last year and the Asiana Airlines crash at San Francisco airport in 2013 that left three dead.
On La Reunion, where a clean-up crew discovered the wreckage and the suitcase, members of the same team yesterday discovered a detergent bottle with Indonesian markings and a bottle of Chinese-branded mineral water, which they took to police.