France said on Monday it wanted to try Libya's former spy chief, Abdullah al-Senussi, over a 1989 airliner bombing in Niger that killed 170 people including 54 French nationals.
A senior Libyan commander said on Monday that his fighters had captured Senussi, who is also wanted by the International Criminal Court.
In 1999 a Paris court convicted six Libyans, including Senussi, and sentenced them in absentia to life imprisonment for the UTA bombing.
A trial in the presence of the accused should be held in France, Foreign Ministry spokesman Bernard Valero said.
Senussi must be judged for the crimes he has committed, Valero said, adding that Paris would consult the various legal entities to ensure he is held accountable for the UTA bombing.
Following the killing of Muammar Gaddafi a month ago, his son Seif al-Islam, who was captured over the weekend, and Senussi were the only surviving Libyans on the wanted list of the ICC.
Libya is standing firm over the trial of the younger Gaddafi, saying its courts can judge him fairly, and defying the ICC, which says it wants to try him at The Hague for crimes against humanity.
(Reporting by John Irish; editing by Geert De Clercq)