Alex Batty, 17, was picked up on the D16 - an unlit single carriageway country road between the French towns of Chalabre and Mirepoix - by Fabien Accidini, a chiropractic student from Toulouse.
Alex Batty, from Oldham, Greater Manchester, was just 11 when he did not return from a holiday to Spain with his mother Melanie, then 37, and grandfather David, then 58, in 2017.
Alex Batty, from Oldham, Lancashire, went missing in 2017 when he was just 11. Detectives believe his mother and grandfather took him as they went to live an alternative lifestyle in southern France.