An appeals court in Paris has ruled that a former member of an Italian radical left-wing group should be extradited back to Italy.
Battisti has become a successful detective writer since moving to France
Cesare Battisti escaped from prison there in 1981 and was later convicted of four murders in absentia, in a trial he says was unfair.
In 1990 he fled to France, where he was granted asylum by then President Francois Mitterrand.
Mr Battisti has the right to appeal against the ruling.
Outside the court, sympathisers held a street protest, watched by heavily armed riot police.
Some leftist groups have urged President Jacques Chirac not to sign the final extradition order.
Mr Battisti, a former member of the Armed Proletarians for Communism, has made a successful career as the writer of detective novels since he moved to France.
An Italian request for his extradition request in 1991 failed.
At the time, France offered sanctuary to former leftist militants from Italy who renounced their violent pasts - an offer taken up by several former guerrillas.
Mr Battisti's lawyer had argued that an extradition request that had already been turned down could not be re-examined.
There were angry protests outside the court
But on Wednesday, the presiding judge at the Paris appeals court, Norbert Gurtner, threw out that line of reasoning and said he would favour the extradition request.
Italian Justice Minister Roberto Castelli welcomed the ruling as an "enormous victory", though he said he expected Mr Battisti to appeal.
"But this sends out an important message to all delinquents and terrorists," he was quoted as saying.
Mr Battisti was sentenced in absentia to carrying out or helping to plan four murders in 1978 and 1979 - including those of a policeman and prison guard.
He says he was not granted a fair trial.
"One particular case, my own, has been removed from the context of the period," he said during a hearing last month.
"It was a social conflict. There were deaths, a lot of
violence. Trials during that period in my view have no value," he said, according to AFP news agency.
His case has become something of a cause celebre, with an internet petition of support attracting 20,000 signatures, including those of some prominent politicians.
Change of climate
Throughout the 1970s and 1980s, groups from Italy's far left and right waged violent campaigns of killings and bombings as they tried to bring down the government.
The French policy of granting amnesty to Italian leftists accused of violent crimes was based on French disapproval at Italy's policy of mass arrests and use of informants.
But the climate has now changed. Some commentators believe France is now concerned it could appear "soft on terror".