PARIS (AP) — French students won’t get past the door if they show up for school wearing long robes, President Emmanuel Macron made clear Friday, saying authorities would be “intractable” in enforcing a new rule when classes resume next week.

French Education Minister Gabriel Attal announced at a news conference four days ago that robes worn mainly by Muslims, known as abayas for girls and women and khamis for boys and men, would be banned with the start of the new school year on Monday.

Macron addressed the dress code for the first publicly after visiting a professional school in the Vaucluse region of southern France

“We know there will be cases” of students testing the rule, the president said, including ones trying to “defy the republican system.” Macron said they would not be able to slip into class, stressing that “we will be intractable on the subject.”

The education minister described girls and boys wearing the robes in junior high and high school as “an infringement on secularism,” a foundational principle for France. He accused some students of using the traditional attire to try to destabilize schools.

The new rule has received inevitable criticism. Social media platforms have buzzed with critics saying the loose, body-covering garments do not constitute an ostentatious display of religion and should not be banned from classrooms.

The framework for the ban is a 2004 law aimed at preserving secularism in French public schools. The law prohibited Muslim headscarves but also applied to large Christian crosses, Jewish kippas and the large turbans worn by Sikhs.

It passed after months of furor and marathon parliamentary debates. Muslims claimed it stigmatized them. The law does not apply to university students.

Addressing how the new measure would be enforced, Macron said “specific personnel” would be sent to “sensitive” schools to help principals and teachers and to dialogue with students and families, if needed.

Attal said earlier that 14,000 educational personnel in leadership positions would be trained by the end of this year to deal with enforcement and other issues in upholding secularism, and 300,000 personnel would be trained by 2025.