France has urged Colombia to reconsider its decision to end the efforts of Venezuelan President Hugo Chavez to negotiate with the Farc rebel group.
President Nicolas Sarkozy said Mr Chavez was still the best person to broker an exchange of 45 of the Farc's hostages for 500 imprisoned guerrillas.
The hostages include Ingrid Betancourt, a French-Colombian kidnapped in 2002.
Earlier, Colombia's president said Mr Chavez had broken an agreement not to speak to the country's army leaders.
The Venezuelan leader had only days ago been given until 31 December to mediate the release of the hostages.
Correspondents say Colombian President Alvaro Uribe had grown frustrated by Mr Chavez and his apparent disregard for following the proper diplomatic channels on the issue since he was invited to mediate in August.
Speaking after Mr Chavez's involvement was "terminated" by Colombia, President Sarkozy's spokesman said France had reiterated its support for the Venezuelan leader's mediation efforts and urged Bogota to restart dialogue with him.
"We continue to think that President Chavez is the best chance of securing the release of Ingrid Betancourt and all the other hostages currently held by the FARC in Colombia," David Martinon told a news conference.
However, Mr Martinon said President Sarkozy would "wait for the temperature to cool a little" before he phoned his Colombian counterpart to discuss the issue.
Ms Betancourt, who has dual Colombian and French nationality, was captured during the presidential election campaign in February 2002 when, against government advice, she tried to reach a remote village used for talks with the Farc.
Her ex-husband, Fabrice Delloye, also expressed his dismay at the Colombian decision.
"This is a tragic step, because whatever President Chavez's personality may be, he was essential in perhaps reaching a humanitarian agreement," he told the radio station France Info.
"Once again, and the world is witnessing it, Colombian President Uribe is an extremely difficult man who can change his views from one day to the next." ( BBC )