Five youths aged 15 to 17 have been taken into custody in eastern France for questioning over the vandalism of Jewish graves, a local prosecutor has said.
All five are from the region of Sarre-Union in Alsace, where about 300 tombs were defaced over the weekend.
The youngest came forward after being shocked by the massive reaction across the country to the vandalism, Philippe Vannier, the prosecutor, said on Monday.
"Apparently, he was very, very affected by the scale of the reaction to this affair, including the statements from the highest state authorities," Vannier told reporters.
Tombstones in the cemetery were pushed over and vaults opened up, while a monument to the victims of the Holocaust at the entrance was also vandalised.
The boy, who was encouraged to hand himself in by one of his friends, has denied any anti-Semitic motive, Vannier added.
"We don't know the motives of these adolescents who don't have past criminal records and we don't know of any ideological convictions that could explain their behaviour," the prosecutor said.
"They are very, very shocked by the turn of events."
The incident was widely condemned by French leaders and leaders of France's Jewish community, the largest in Europe, on Sunday.
It also spurred Israeli Prime Minister Benjamin Netanyahu to call for Europe's Jews to emigrate to Israel.
Netanyahu's comments prompted French President Francois Hollande to say that Jews were welcome in
Europe and France and French Prime Minister Manuel Valls to add: "The place for French Jews is France."
Hollande will visit the area on Tuesday.