VANNES, France — The ex-wife of a former surgeon at the center of France’s largest ever child sexual abuse case told a court Wednesday she knew “nothing” of her husband’s near 30-year history of abusing children, including members of their family, until his arrest in 2017.

Marie-France Lhermite, 71, testified as her ex-husband, Joël Le Scouarnec, watched in the Palais de Justice in Vannes, a town in Brittany, northwestern France, where most of the alleged assaults took place.

“I…