The France 24 journalist was seized last month in a FARC attack on a Colombian army unit engaged in counter-narcotics operations.
His capture came almost exactly two years to the day after he did a special report on whether the guerrillas could keep fighting after their leader and a top military commander were killed.
Langlois, a correspondent with more than 10 years experience in the country, appears to have spent several days with a mobile FARC unit to prepare the April 2010 report.
He described them as “in a weak position” and said they were “tired of fighting for 40 years in the jungle.”
He was reporting alongside soldiers when the rebel group attacked and captured him on April 28, the Colombian government said. Four people were killed and six were wounded in the attack, according to the Ministry of National Defense.
Langlois was lightly wounded in the arm when he was captured, but was treated and is out of danger, according to a man who claimed to represent the rebels.
The man in military garb referred to Langlois as a prisoner of war in a video posted on the France 24 website on May 7.
FARC announced a week later that it was prepared to release the Frenchman and called for negotiations involving the International Committee of the Red Cross and others.