Under-fire France claims Muslim overgarment abaya is a 'political sign'
Government spokesman Olivier Veran says clothing is "obviously" a religious garment, which is an act of "proselytising" or trying to convert to Islam.
The wearing of abaya dresses by some Muslim women in schools is a "political attack", the French government has said as it defended a ban on the clothing amid growing anger.
Education Minister Gabriel Attal said on Sunday that the long, flowing dresses that cover the entire body would no longer be allowed in schools when the new term begins next week because they violate secular laws.
Government spokesman Olivier Veran said on Monday that it was "obviously" a religious garment and "a political attack, a political sign", which he saw as an act of "proselytising" or trying to convert to Islam.
"School is secular. We say it in a very calm but firm way: it is not the place for that (wearing religious clothing)," he told the BFM TV channel.
Attal said Monday that the government was clear that abayas "did not belong in schools."
"Our schools are being tested. These last few months, violations of our secular rules have considerably increased, particularly with regard to the wearing of religious clothing such as abayas or qamis which have appeared - and remained - in some establishments," he told reporters.
Attal's decision to ban abayas has sparked a new debate about France's secular rules and whether they are used to discriminate against the country's large Muslim minority.
Secular rules as a front
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 Christian crosses, Jewish kippas and Islamic headscarves.
The government has sided with politicians on the right and far-right who had pushed for an outright ban, arguing that they are part of a wider agenda to spread religious practice throughout society.
But politicians on the left and many Muslims see France's secular rules - known as "laicite" - as a front used by conservatives for Islamophobic policies.
They say some women choose to wear abayas, or headscarves, to signal their cultural identity, rather than out of religious belief.
Many conservative politicians have pushed in recent years for the ban on the wearing of religious symbols to be widened to universities and even parents accompanying children on their school outings.
Far-right leader Marine Le Pen campaigned in last year's presidential election to ban veils from all public streets.
The abaya ban is likely to face a legal appeal and could lead to difficulties for school authorities who will have to decide when a large flowing dress moves from being a personal fashion choice to a religious statement, observers say.