(AFP) - French authorities are to ban the wearing in school of abaya dresses worn by some Muslim women, the education minister said Sunday, arguing the garment violated France's strict secular laws in education.

"It will no longer be possible to wear an abaya at school," Education Minister Gabriel Attal told TF1 television, saying he would give "clear rules at the national level" to school heads ahead of the return to classes nationwide from September 4.

The move comes after months of debate over the wearing of abayas in French schools, where women have long been banned from wearing the Islamic headscarf.

The right and far-right had pushed for the ban, which the left argued would encroach on civil liberties.

There have been reports of abayas being increasingly worn in schools and tensions within school over the issue between teachers and parents.

"Secularism means the freedom to emancipate oneself through school," Attal said, describing the abaya as "a religious gesture, aimed at testing the resistance of the republic toward the secular sanctuary that school must constitute.

"You enter a classroom, you must not be able to identify the religion of the students by looking at them," he said.

A law of March 2004 banned "the wearing of signs or outfits by which students ostensibly show a religious affiliation" in schools.

This includes large crosses, Jewish kippas and Islamic headscarves.

Unlike headscarves, abayas -- a long, baggy garment worn to comply with Islamic beliefs on modest dress -- occupied a grey area and had faced no outright ban until now.

But the education ministry had already issued a circular on the issue in November last year.

It described the abaya as one of a group of items of clothing whose wearing could be banned if they were "worn in a manner as to openly display a religious affiliation". The circular put bandanas and long skirts in the same category.

- Mixed reaction -

Approached by head teachers' unions about the issue, Attal's predecessor as education minister Pap Ndiaye replied that he did not want "to publish endless catalogues to specify the lengths of dresses".

At least one union leader, Bruno Bobkiewicz, welcomed Attal's announcement Sunday.

"The instructions were not clear, now they are and we welcome it," said Bobkiewicz, general secretary of the NPDEN-UNSA, which represents head teachers.

Eric Ciotto, head of the opposition right-wing Republicans party, also welcomed the news.

"We called for the ban on abayas in our schools several times," he said.

But Clementine Autain of the left-wing opposition France Unbowed party denounced what she described as the "policing of clothing".

Attal's announcement was "unconstitutional" and against the founding principles of France's secular values, she argued -- and symptomatic of the government's "obsessive rejection of Muslims".

Barely back from the summer break, she said, President Emmanuel Macron's administration was already trying to compete with Marine Le Pen's far-right National Rally.

The debate has intensified since a radicalised Chechen refugee beheaded teacher Samuel Paty, who had shown students caricatures of the Prophet Mohammed, near his school in a Paris suburb in 2020.

The CFCM, a national body encompassing many Muslim associations, has said items of clothing alone are not "a religious sign".

The announcement is the first major move by Attal, 34, since he was promoted this summer to handle the hugely contentious education portfolio.

Along with Interior Minister Gerald Darmanin, 40, he is seen as a rising star who could potentially play an important role after Macron steps down in 2027.

© Agence France-Presse