He is expected to give evidence at the trial of his parents, aunts and uncle, who are accused of systematically starving and torturing him until he was four.
The slight, blond child was tied to posts, struck with hammers, saucepans and fists, rolled in nettles and forced to sleep with the pigs at the family farm in Vosges, eastern France.
Asked why the boy was abused daily by his closest relatives, his aunt, Muriel Theveniaud, 23, told an investigating magistrate: "It amused everyone to see him suffer."
The story of "le petit Johnny" horrified France when it became known, three years ago. Yesterday his mother and stepfather, Sandra and Rene Grenglet, went on trial in Epinal for "acts of torture and barbarism" against a minor. His uncle and two aunts face similar charges; his grandfather and another uncle are accused of failing to come to his assistance.
The child's misery ended when a plumber working at the family home reported to the gendarmerie that he had seen an emaciated and withdrawn child standing looking at the wall, his face covered in bruises. Family members later admitted that the boy had been beaten and humiliated from morning to night, for no particular reason.
Johnny now lives with a foster family. In an interview on Monday, he was asked if he wanted to see his parents again. He turned away and replied: "Je n'ai pas envie [I don't want to]."
Psychiatric reports presented at the trial described the boy's mother as a woman of "limited independence" who had been sexually abused as a child. She had wanted the boy to suffer as she had done. His stepfather also had a history of abuse in childhood.