The French prime minister, Gabriel Attal, has defended French secularism following the resignation of a Paris school principal who received death threats after asking a student to remove her Muslim veil on the premises.

Attal, a former education minister, said the state would be filing a complaint against the student over falsely accusing the headmaster of mistreatment during the incident in late February.

“The state … will always stand with these officials, those who are on the frontline faced with these breaches of secularism, these attempts of Islamist entryism in our education establishments,” he said during the evening news on the TF1 television channel.

Secularism and religion are hot-button issues in France, which is home to Europe’s largest Muslim community.

In 2004, authorities banned schoolchildren from wearing “signs or outfits by which students ostensibly show a religious affiliation” such as headscarves, turbans or kippas on the basis of the country’s secular laws, which are meant to guarantee neutrality in state institutions.

The headteacher’s departure comes amid deep tensions in the country after a series of incidents including the killing of a teacher by an Islamist former pupil last year.

The head at the Maurice Ravel lycée in eastern Paris quit after receiving death threats online following an altercation with a student last month, officials told AFP.

In late February he had asked three students to remove their Islamic headscarves on school premises, but one of them refused and an altercation ensued, according to prosecutors. The head later received death threats online.

According to a letter sent by the school to teachers, pupils and parents, the principal stood down for “security reasons”, while education officials said he had taken “early retirement”.

In a message addressed to the school’s staff, quoted by French communist daily L’Humanité, the principal said he had taken the decision to leave “for his own safety and that of the school”.

“It’s a disgrace,” Bruno Retailleau, the head of the right-wing Republicans faction in the Senate upper house, said on X on Wednesday.

“We can’t accept it,” Boris Vallaud, the head of the Socialist deputies in the National Assembly lower house, told television broadcaster France 2, calling the incident “a collective failure”.

Marion Maréchal, granddaughter of far-right patriarch Jean-Marie Le Pen and a far-right politician herself, spoke on Sud Radio of a “defeat of the state” in the face of “the Islamist gangrene”.

Maud Bregeon, a lawmaker with President Emmanuel Macron’s Renaissance party, also took aim at “an Islamist movement”.

“Authority lies with school heads and teachers, and we have a duty to support this educational community,” Bregeon said.

The Socialist mayor of Paris, Anne Hidalgo, called the principal to “assure him of her total support and solidarity”, said her office, adding she was “appalled and dismayed”.

The student lodged a complaint against the principal, accusing him of mistreating her during the incident. She told French daily Le Parisien that she had been “hit hard on the arm” by the principal.

The student is an adult who was at the school for vocational training.

The Paris public prosecutor’s office told AFP on Wednesday that her complaint had been dismissed.

At the same time, an investigation was opened into cyber-harassment after the death threats against the head.

In a further show of support, the education ministry said in a statement that it would never abandon teachers in the face of threats.

The ministry said that “all teams” remained mobilised, adding that the principal’s decision to leave his post was “understandable given the seriousness of the attacks against him”.

Education minister Nicole Belloubet visited the school in early March and deplored the “unacceptable attacks”.

A 26-year-old man has been arrested for making death threats against the principal on the internet. He is due to stand trial in April.