A high school student entered a school in western France's Nantes with a knife and stabbed at least four students, local media reported, citing the police.
One of the victims died from injuries, according to BFMTV on Thursday, citing multiple sources.
Teachers stopped the attacker before police arrived, BFMTV said, adding that the attacker, a second-year high school student, has been detained, news agency reported.
The youth -- whose identity has not been revealed but who had expressed an admiration for Adolf Hitler -- was overcome by teachers after staging attacks in several classrooms, witnesses said.
He was detained by police but hospitalised after a psychiatric examination.