Speaking on Radio France Inter, Francois Fillon said the state would be ready to expel any girl who wore a headscarf to a state school.
“I will personally ensure that there are no exceptions, the Republic will stand firm,” Mr Fillon said.
He urged leaders of Muslim groups not to inflame and politicise the issue.
Religious symbols
France’s Muslim groups, who represent some of the country’s estimated five million Muslims, responded angrily when the ban on headscarves and other overt religious symbols in state schools became law in March.
Proponents of the ban on religious insignia in the classroom argue it equally applies to Jewish skullcaps and Christian crucifixes.