Caroline Dickinson was murdered on a school trip
Francisco Montez was given over to American federal marshals in Miami on Monday.
He was put on board an Air France flight and arrived in Paris on Tuesday morning, to face questioning by French investigators.
The Spanish waiter is alleged to have raped and murdered the 13-year-old girl in a hostel room in Brittany, during a school trip in July 1996.
On arrival at Charles-De-Gaulle airport in Paris, Mr Montez was notified of the international warrant for his arrest, then handed over to a prison officer.
Chance breakthrough
He was due to be taken to the law-courts at the nearby town of Bobigny for an interview with a state prosecutor, and from there to the city of Rennes, in Brittany.
US prosecutors had freed the 51-year-old of unrelated state charges, clearing the way for him to be flown to France.
Caroline's father John, of Bodmin, Cornwall, said he thought it was inappropriate for the family to comment while legal proceedings were pending in France.
The breakthrough in the hunt for Mr Montez, whose name had been put forward as a suspect, came when a US immigration officer read about the case while on holiday in London.
Tommy Ontko checked files on his return to Miami, discovering the suspect had been arrested there a few days earlier on unrelated charges.
Under the deal, he would have been freed from local prison if he had pleaded guilty to charges of burglary and lewd behaviour, brought after he was arrested in the Miami Beach area in March.
When he refused, prosecuters then moved to reduce the bail, setting him free from local custody and enabling the extradition process to begin.
"We basically took our handcuffs off him and the federal marshals put theirs on," said Florida State Attorney spokesman.
DNA evidence
The marshals, who had a State Department arrest warrant, took him into custody.
French police were waiting at Miami International Airport to take Mr Montez into their custody.
The State Department warrant was issued after the FBI had confirmed that Mr Montez is not a suspect in any other crimes in America.
"His DNA and modus operandi were checked before the warrant was issued," said a spokesman.
A Devon and Cornwall police spokesman said the latest development was "very welcome".
He said: "We anticipated months of delay before we could take this investigation further forward.
"We are liaising closely with the French authorities, and we will be contacting them imminently to discuss the way forward."
The extradition is believed to be the first in American legal history based on DNA evidence.