Teachers at a school outside Paris refused to work on Monday as the establishment grappled with a crisis sparked by the showing in class of a painting by a Renaissance master containing several nude women.
Education Minister Gabriel Attal visited the Jacques-Cartier middle school in Issou, west of Paris, in person on Monday and later said the pupils concerned would be disciplined.
On Thursday, "during a French class, a colleague showed a 17th-century painting that showed naked women", said Sophie Venetitay, secretary general of the Snes-FSU secondary school teachers' union.
The painting, "Diana and Actaeon" by the Italian painter Giuseppe Cesari, portrays a Greek mythology story in which the hunter Actaeon bursts in at a site where the goddess Diana and her nymphs are bathing.
The work, which shows a naked Diana and four female companions, is held at the Louvre museum in Paris.
"Some students averted their gaze, felt offended, said they were shocked," Venetitay said, adding that "some also alleged the teacher made racist comments" during a class discussion.
A pupil's parent sent an email to the school director saying that his son was prevented from speaking during that discussion and that he would file a complaint, she said.
She said it was the "final straw" for teachers at the school, who had complained of a "very degraded climate" as well as a "lack of support" from management despite "several alerts".
In an email sent to parents on Friday, and seen by AFP, teachers said they were exercising their right to stay away from classrooms over the "particularly difficult situation" at the high school.
They described "palpable discomfort" and "an increase in cases of violence" as their daily reality.
Attal said that a disciplinary procedure would be launched "against the students who are responsible for this situation and who have also admitted the facts".
A team would also be deployed to the school to ensure it adhered to the "values of the republic", he said.
The tensions come after a series of attacks against teachers in recent years.
A French court on Friday convicted six teenagers for their role in the 2020 killing of Samuel Paty outside his secondary school near Paris by a radicalised Islamist.
Paty, a 47-year-old history and geography teacher, was stabbed and beheaded in the Paris suburb of Conflans-Sainte-Honorine in October 2020.
His murder came after messages spread on social media that Paty had shown his class cartoons of the Prophet Mohammed from the satirical magazine Charlie Hebdo.
In October, another radicalised Islamist stabbed his former teacher Dominique Bernard to death in the northern town of Arras.
