French Education Minister Gabriel Attal has visited a school where pupils refused to look at a 17th-Century painting portraying nude women.
Several first-year high school students said they were offended by the work by the Italian painter Giuseppe Cesari.
They later claimed their teacher had made racist and Islamophobic remarks - a claim denied by the school.
Teachers at the Jacques-Cartier school in Issou, near Paris, refused to work in response to the incident.
The painting in question, entitled Diana and Actaeon, dates from the Renaissance era and portrays a mythical scene from the Roman poet Ovid's Metamorphoses.
In the story, the hunter Actaeon surprises the goddess Diana and her nymphs bathing. The Cesari painting, which hangs in the Louvre, portrays Diana and four female nymphs fully nude.
On 7 December, a French teacher showed the painting to her class. "Students looked away, felt offended, said they were shocked," said Sophie Vénétitay, general secretary of the Snes-FSU teachers' union.
The next day, according to French reports, a parent wrote to the head teacher claiming that his son had been prevented from expressing himself in a later class discussion.
Tensions have apparently been high at the school since the start of term in September, with officials detailing repeated complaints by parents about coursework and punishments.
Ms Vénétitay said that the latest incident recalled the brutal killing of Samuel Paty, a history and geography teacher who was murdered three years ago after he showed a class caricatures of the Prophet Muhammad.
French authorities believe untrue rumours spread about the class contributed to inciting an 18-year-old radicalised Chechen refugee to murder him close to the teacher's school in a Paris suburb.
Last week, six teenagers were convicted for their role in the murder.
Mr Attal told the press that disciplinary procedures would be launched against the students.
On Tuesday, classes at the school restarted after several days' interruption. Staff at the Jacques-Cartier school had refused to teach following the incident, which they said was symptomatic of a breakdown in authority there.
Mr Attal said that the school's teachers had his "full support".
