France's highest administrative court on Friday suspended a ban on the Islamic burkini swimsuit brought by a French Riviera town after it was challenged by rights groups.
In a judgement expected to set a precedent, the State Council ruled that local authorities could only restrict individual liberties if there was a "proven risk" to public order.
The case before the court concerned the French Riviera resort of Villeneuve-Loubet, one of around 30 towns which have passed burkini bans.
The French Council of the Muslim Faith (CFCM) hailed the ruling as "a victory for common sense".
Amnesty International too welcomed the ruling.
"By overturning a discriminatory ban that is fuelled by and is fuelling prejudice and intolerance, today's decision has drawn an important line in the sand," Amnesty's Europe director John Dalhuisen said.
"French authorities must now drop the pretence that these measures do anything to protect the rights of women," he said.
The CFCM's secretary general Abdallah Zekri said: "This victory for common sense will help to take the tension out of a situation which has become very tense for our Muslim compatriots, especially women."
The State Council heard arguments from the Human Rights League and an anti-Islamophobia group.
The burkini bans had triggered a fierce debate about the wearing of the full-body swimsuit, women's rights and the French state's strictly-guarded secularism.
President Francois Hollande said on Thursday that life in France "supposes that everyone sticks to the rules and that there is neither provocation nor stigmatisation".
London Mayor Sadiq Khan, the first Muslim mayor of a major Western capital, condemned the bans as he visited Paris Thursday.
"I don't think anyone should tell women what they can and can't wear. Full stop," he told the London Evening Standard newspaper.
Police have fined Muslim women for wearing burkinis on beaches in towns including in the renowned Riviera resorts of Nice and Cannes.
The office of Nice's mayor denied that the woman had been forced to remove clothing, telling AFP that she was showing police the swimsuit she was wearing under her top, over a pair of leggings, when the picture was taken. The police fined her and she left the beach, the officials added.
The first ban on the burkini has been attributed to Mandelieu-la-Napoule, close to Cannes, where it was discreetly barred in July 2013. The text of the municipal decree has been used, typically word for word, in bans elsewhere.
Cannes mayor David Lisnard said he had signed off on the burkini ban out of "respect for good customs and secularism", a founding principle of the French republic.