Articles in three magazines, L'Express, Challenges and Vanity Fair, quote negotiators saying that efforts to free Dol and three other hostages were held up in April 2012 on the orders of General Benoît Puga, at the time the military chief of staff of then-president Nicolas Sarkozy.
The four - Dol, Marc Féret, Pierre Legrand and Daniel Larribe - worked for energy giant Areva at a uranium mine in Niger in 2010 when they were kidnapped by Al Qaeda in the Islamic Maghreb (Aqim).
After speaking to negotiators Jean-Marc Gadouillet and Pierre-Antoine Lorenzi, the magazines conclude that Aqim hostage-taker Abou Zeid was prepared to release at least one of them - if not all four - in April 2012, while Sarkozy was fighting his unsuccessful campaign to be reelected.
Rescue called off
After three hostages were freed for 12.5 million euros in February 2011, Gadoullet reportedly obtained a promise to release Féret, for a further 6.5 million euros, according to L'Express.
In May 2012, as Tuareg rebels launched a rebellion in northern Mali where the hostages were being held, a mission to collect Féret and negotiate for the remaining three was called off at the orders of the Elysée, it says.
Believing that their release had been unnecessarily delayed but without knowing the details, Dol and Féret had already filed a legal case for complicity in kidnapping and failure to help someone in danger at the end of last year, with their lawyers claiming their had been obstruction "at the highest level of the state".
Did Sarkozy know?
The latest articles indicate that the order to call of the operation came from Puga and ask whether it was given with Sarkozy's knowledge.
"One day the secrets of the Elysée have to be cleared up, former president Nicolas Sarkozy will have to say something and that François Hollande, who was elected in May 2012, will have to give all the details," Dol told RFI, adding that the mystery is hindering the hostages' recovery from their ordeal.
"That's why I'm asking the president of the republic to tell us if these allegations are false."
Suing government to know truth
Dol intends to sue the government, a complicated process in France, and has started proceedings against the president, the prime minister and the foreign affairs minister as a first step.
Neither Puga, who kept his job after Hollande was elected in 2012, nor Sarkozy have responded to requests for interviews from L'Express.
The hostages were finally released in October 2013.