Alex Batty, now 17, was allegedly abducted by his mother, Melanie Batty, and grandfather, David Batty.
He was under the guardianship of his grandmother Susan Caruana at the time of his disappearance. She believed he was taken by her daughter and ex-partner because they wanted him to live “an alternative lifestyle.”
The La Depeche du Midi newspaper reported that he had been found by a passing motorist, a student from Toulouse named Fabien Accidini, after wandering for several days in a mountainous area.
Accidini said: “He was walking while the rain fell in heavy drops. The second time I passed him, I decided to offer to drop him off somewhere.
“He was quite tall and blond, and dressed in black jeans, a white sweater and a backpack. He also carried a skateboard under his arm and a flashlight for lighting. His attitude gave me confidence. He ended up getting into my van.
“During the first few minutes, he seemed a little shy. We tried to speak in French but I noticed that he had not mastered the language. I decided to communicate in English. When I asked him his name, he pretended his name was Zach, and then we continued chatting.
“We talked for over three hours. Very quickly, he gave me his real identity – Alex Batty – before telling me his story.”
Batty explained he had lived with his mother in a “spiritual community” and had “no animosity" towards her but wanted to find his grandmother. He added that he had been living “in Spain in a luxury house with around 10 people for three years”.
Greater Manchester Police, who have been working with French authorities, said: “This is a complex and long-running investigation, and we need to make further inquiries as well as putting appropriate safeguarding measures in place.”
The boy’s grandmother, Ms Caruana said: “The reason I believe they have done this is because basically my lifestyle, my belief systems, are not what they agree with – just simply living day to day, how normal people do.
“They didn’t want him to go to school, they don’t believe in mainstream school.”
The UK Foreign Office said in a statement: “We are supporting a British national in France and are in contact with local authorities.”
