Ayat Allah Ahmad Jannati called on Islamic countries to "threaten France with cancelling contracts and to reconsider their relations with France" over the issue.
After months of heated debate, a committee of French experts recommended in December banning "conspicuous" religious insignia from state schools, which are secular.
These would include the Islamic headscarf, the Jewish kippa and large crucifixes.
In a subsequent speech, French President Jacques Chirac came out in favour of the ban, which he wants written into law by the start of the next academic year.
But Jannati assured worshippers that all that was necessary was "a roar from Muslims, and the French would back off".
He called on the French authorities to "let Muslim women express their freedom and carry out their religious obligations".
Khatami says the hijab is a
Ever since Chirac spoke on 17 December, Muslim countries have been voicing outrage at the proposed ban.
Numerous Iranian officials, including President Muhammad Khatami and nearly 200 members of parliament, have already called on the French authorities to reject the proposal.
"I hope the French government, which claims to be avant-garde in liberty, equality and fraternity, will cancel this wrong decision," Khatami said last week.
He said the "hijab is a religious necessity and its restriction is a sign of a kind of extreme nationalistic tendency".
On Monday, around 150 students demonstrated in front of the French embassy in Tehran shouting "death to France" and "death to Chirac the Zionist".