In Paris and other French cities, protesters marched against the law proposed by President Jacques Chirac that would ban Muslim headscarves, Jewish skullcaps and large Christian crosses from state schools.
The demonstrations in France took place under close police surveillance after the government warned on Friday of attempts to stir up radical opposition to the ban.
Protests began first in Jordan and London. Dozens of women protested outside the French embassy in Amman, holding up banners that read: "My veil is my freedom" and "Banning hijab is a confusion of freedom".
In London, an estimated 2000 people marched on the French embassy in central London to protest against plans by the French government to ban the Islamic headscarf from schools.
Demonstrators issued a statement saying: "The banning of the Islamic headscarf in France has opened up a new front in the war on Islam."
"The aim is to ban the public expression of Islam in Europe in the name of secularism," the text charged.
In Britain, the wearing of a Muslim headscarf or Sikh turban or Jewish kippa is not an issue and the proposed law to ban conspicuous religious insignia has provoked outrage in the Muslim community there.
On Friday, French government spokesman Jean-Francois Cope defended the ban as an effort to uphold France's commitment to keep church and state separate, and hit out at what he said were attempts to stir up radical opposition to the measure.
Many French politicians and voters support the planned law as a bulwark against Islamist influence among Muslim immigrants.
It has divided opinion among France's five million Muslims, and been criticised by Muslims abroad.
Protesters say hijab ban questions
French ''liberty, equality & fraternity''
In Amman, Muna Abu Dabbus, an activist in Jordan's Islamic Action Front, who took part in the protest said Jordanian women were protesting in solidarity with their sisters in France.
"France is a democratic country and democratic countries give the citizens the right to practise their religion," she said. "My hijab is my right and my freedom. It gives me the freedom to do what I want."
Dalil Boubakeur, chairman of the French Council of the Muslim Faith (CFCM), has described the march in Paris as a "very dangerous" measure that could frighten voters two months before regional elections are held across France.
Other Muslims feel unfairly targeted by Chirac's plan. A pro-headscarf march in Paris last month rallied more than 3000 people, many of them young women in hijab.
Chirac's centre-right government wants to rush the anti-headscarf law through parliament so debate starts before the regional elections and the ban is effective by September.
In Indian-administered Kashmir, activists of a Muslim women's group on Saturday held a demonstration to protest plans by the French government to ban the Islamic headscarf from state schools.
Kashmiri women say the ban is a
ban on Islam's basic principles
Several dozen activists from the separatist group Dukhtaran-e-Milat or Daughters of the Faith held a noisy demonstration in Srinagar, the summer capital of Indian Kashmir, despite a heavy downpour and Himalayan chill.
Donning the hijab, the activists of the staunchly pro-Pakistan group shouted slogans against the French government.
They carried banners reading: "Hijab is the identity of a Muslim woman so to ban it is actually to ban basic principles of Islam."
One huge banner decried the French government's decision.