France has called for the release of Colombian ex-presidential candidate Ingrid Betancourt on the fourth anniversary of her abduction.
A portrait of Betancourt was unveiled outside the French Senate
She is being held by Colombia's largest rebel group, the Revolutionary Armed Forces of Colombia, the Farc.
Mrs Betancourt holds both Colombian and French citizenship.
Talks between the Farc and the government of President Alvaro Uribe about an exchange of hostages for jailed rebels have broken down.
Mrs Betancourt is one of about 60 political hostages held by the Farc.
French Prime Minister Dominique de Villepin said on Thursday that Mrs Betancourt's abduction was a horrible drama.
"Four years is a veritable tragedy. I hope that we will have new proof that Ingrid is alive very quickly," he said.
Friends and relatives of the Colombian politician held a ceremony in Paris to mark the fourth anniversary of her captivity.
They dropped roses into the River Seine as a boat sailed past carrying a banner calling for the liberation of the hostages.
They also unveiled a portrait of Mrs Betancourt in front of the French Senate.
A week of events, including theatre performances, is under way in France to draw attention to her case and other kidnappings.