ISTANBUL — A 50-year-old Frenchman who was snatched from his hotel room in Mali by Al Qaeda’s affiliate in North Africa and held captive for more than three years was released, President François Hollande of France announced on Tuesday.

“It’s a day of joy,” Mr. Hollande said in a video posted on the government’s website. “Our hostage Serge Lazarevic — our last hostage — is free.”

Even as France celebrated Mr. Lazarevic’s return from captivity in the burning sands and craggy caves of the Sahara, questions were being asked about what concessions the French government made to the extremist group, Al Qaeda in the Islamic Maghreb, that held him.

The liberation of Mr. Lazarevic comes after reports that two militants imprisoned in Mali, including one who was directly involved in the kidnapping of Mr. Lazarevic, were freed as part of a prisoner exchange. Officials declined to comment on the terms of the Frenchman’s release, including whether a ransom had been paid by France, where the government has a history of paying millions in cash to win its citizens’ freedom from kidnappers.