Schoolgirls who refused to change out of the loose-fitting robes have been sent home with a letter to parents on secularism.

French public schools have sent dozens of girls home for refusing to remove their abayas – long, loose-fitting robes worn by some Muslim women and girls – on the first day of the school year, according to Education Minister Gabriel Attal.

Defying a ban on the garment seen as a religious symbol, nearly 300 girls showed up on Monday morning wearing abayas, Attal told the BFM broadcaster on Tuesday.

Most agreed to change out of the robe, but 67 refused and were sent home, he said.

The government announced last month it was banning the abaya in schools, saying it broke the rules on secularism in education that have already seen headscarves forbidden on the grounds they constitute a display of religious affiliation.

The move gladdened the political right but the hard left argued it represented an affront to civil liberties.

The 34-year-old minister said the girls refused entry on Monday were given a letter addressed to their families saying that “secularism is not a constraint, it is a liberty”.

If they showed up at school again wearing the gown there would be a “new dialogue”.

He added that he was in favour of trialling school uniforms or a dress code amid the debate over the ban.

Uniforms have not been obligatory in French schools since 1968 but have regularly come back on the political agenda, often pushed by conservative and far-right politicians.

Attal said he would provide a timetable later this year for carrying out a trial run of uniforms with any schools that agree to participate.

“I don’t think that the school uniform is a miracle solution that solves all problems related to harassment, social inequalities or secularism,” he said.

But he added: “We must go through experiments, try things out” in order to promote debate, he said.

‘Worst consequences’

Al Jazeera’s Natacha Butler, reporting from Paris before the ban came into force said Attal deemed the abaya a religious symbol which violates French secularism.

“Since 2004, in France, religious signs and symbols have been banned in schools, including headscarves, kippas and crosses,” she said.

“Gabriel Attal, the education minister, says that no one should walk into a classroom wearing something which could suggest what their religion is.”

On Monday, President Emmanuel Macron defended the controversial measure, saying there was a “minority” in France who “hijack a religion and challenge the republic and secularism”.

He said it leads to the “worst consequences” such as the murder three years ago of teacher Samuel Paty for showing Prophet Muhammad caricatures during a civics education class.

“We cannot act as if the terrorist attack, the murder of Samuel Paty, had not happened,” he said in an interview with the YouTube channel, HugoDecrypte.

An association representing Muslims has filed a motion with the State Council, France’s highest court for complaints against state authorities, for an injunction against the ban on the abaya and the qamis, its equivalent dress for men.

The Action for the Rights of Muslims (ADM) motion is to be examined later on Tuesday.