A boy featured in a chilling Islamic State propaganda video showing the killing of a Palestinian is said to have been recognized by classmates in Toulouse, AFP reported Friday, citing an official.

"Concerning the formal identification of this person, I cannot tell you anything," the schools inspector in the Haute-Garonne district in southern France, Jacques Caillaut, was quoted as saying. "Children from the Vauquelin College have recognized one of their classmates, but we must remain cautious."

According to Caillaut, students at Vauquelin secondary school would have known the boy, who is said to be no older than 12, when he was in primary school. He said the students had seen the video on Wednesday and were provided with counselling.

"There is a child who has not been enrolled at the Vergers (primary) school since March 14, 2014, but I do not have any other details," Caillaut was quoted as saying.

The video claims to show the execution of East Jerusalem Palestinian Muhammad Musallam, 19, who was taken hostage as an alleged Israeli spy three months ago in Syria.

The video, published by the group's Furqan media outlet, showed Musallam sitting in a room wearing an orange jumpsuit, talking about how he had been recruited and trained by the Israeli intelligence service. He says his father and elder brother had encouraged him.

After that, it showed Musallam being escorted to a field and executed by the boy, described by an older, French-speaking fighter as one of the "cubs of the caliphate".

Investigators are looking into whether the latter fighter is related to an extremist who attacked a Jewish school in Toulouse in 2012.