Investigators seem increasingly confident the debris came from a Boeing 777, the type of aircraft that disappeared after leaving Kuala Lumpur, Malaysia on a flight to Beijing on March 8, 2014. The piece was discovered this week on the island of Reunion.
Work to conclusively identify it will begin midweek, French prosecutors said.
Boeing said it is sending experts to France, and the U.S. National Transportation Safety Board will also join the probe, a source with knowledge of the investigation said.
A preliminary report could come as early as next week, a source close to the French investigation said.
If confirmed, the piece of wreckage would be the first bit of physical evidence recovered from MH370. It could help resolve some questions about the fate of the aircraft, which vanished without a trace in March 2014.
The part turned up this week on the shore of Reunion, an island in the western Indian Ocean, more than 2,000 miles from the search zone.
"I thought perhaps it's from a plane crash so I said don't touch it anymore," said Johnny Begue, who was the first to spot the debris. "Because if it's a plane crash, then people have died and you have to [have] respect for them."
To experts, it looks a lot like a flaperon, part of an aircraft's wing that helps control its speed and banking angle.
Boeing investigators said they are confident the debris is from a 777 aircraft, according to a source close to the investigation.
The source said Boeing investigators are basing their view on photos that have been analyzed and a stenciled number that corresponds to a 777 component.
Another source told CNN that Boeing engineers have seen a part number -- 10-60754-1133 -- in photos of the component. A Boeing parts supplier confirmed the number was on a seal associated with the Boeing 777, the source said. A component number is not the same as a part number, which is generally much longer.
Images of the debris appear to match schematic drawings for the right-wing flaperon from a 777.
Malaysia's deputy minister of transport, Abdul Aziz Kaprawi, also weighed in, saying the part "most certainly belongs to a Boeing 777." But he didn't draw any more direct connection between the part and the missing flight. A French aeronautics investigator familiar with the ongoing investigation agreed.
Martin Dolan, the head of the Australian agency coordinating the underwater search for the plane, said he is "increasingly confident but not yet certain" that the debris is from MH370.
But, he said, "the only 777 aircraft that we're aware of in the Indian Ocean that could have led to this part floating is MH370."
SUITCASE WASHES ASHORE
New debris, which washed ashore Thursday and appears to resemble remnants of a suitcase, is also part of the investigation, Reunion Island police officials said.
But Australian Deputy Prime Minister Warren Truss said officials were less sure that "the bag has anything to do with MH370" than they are about the plane component.
Teams in Reunion have continued to search the stretch of coast where the debris was found.
The debris was placed in a crate for the trip to France, where it will be taken to a lab operated by the French General Directorate of Armament. That agency has sophisticated equipment and expertise to quickly identify the plane the debris belongs to and what happened to it, a source close to the French investigation told CNN.
That analysis will begin on Wednesday, the Paris prosecutor's office said in a statement.
Malaysia, which is responsible for the overall investigation into MH370's disappearance, is sending teams of aviation officials to Toulouse, where investigators will analyze it, and Reunion, the country's Prime Minister said Thursday.
It's unclear when the identification process will be completed and its results announced.
Authorities have so far been unable to establish why Flight 370 flew sharply off its route from Kuala Lumpur, Malaysia, to Beijing and disappeared on March 8, 2014.
A preliminary assessment by U.S. intelligence agencies
, produced in the wake of the MH370 disaster, suggested someone in the cockpit deliberately caused the aircraft's movements before the Malaysian airliner disappeared.
Two U.S. officials briefed on the matter told CNN that the assessment, which was not intended for public release, was prepared months ago and was solely based on available satellite and other evidence.
The U.S. intelligence assessment
was largely focused on the multiple course changes the aircraft made after it deviated from its scheduled Kuala Lumpur-to-Beijing route. Analysts determined that, absent any other evidence, it's most likely someone in the cockpit deliberately moved the aircraft to specific waypoints, crossing Indonesian territory and eventually toward the south Indian Ocean.
Malaysian investigators haven't reported finding any evidence that casts suspicion on the pilots.
The airliner's crew has been the focus of attention since the mysterious disappearance, but no proof has emerged indicating they intended to destroy the plane
. Law enforcement and intelligence agencies from numerous countries examined the plane's manifest of crew and passengers and found no significant information to suggest anyone on board posed an obvious threat.
Confirming that the part is from MH370 would establish "really beyond any doubt" that Flight 370 ended its journey in the Indian Ocean, Australia's Truss said.
It would also bolster Australian officials' confidence that they are searching for the rest of the plane's wreckage in roughly the right place, he said, as models of ocean currents make it credible that some debris would drift to the region around Reunion.
But the wreckage is unlikely to help with the underwater search for the remains of the plane, which is taking place in a remote part of the southern Indian Ocean, far off the western coast of Australia.
Investigators need to find Flight 370's flight recorders to have any hope of gleaning a better understanding of what happened on board the plane.