A French judge rejected on Saturday a demand by a French Muslim group to overturn a ban on burkinis -- the full-body, head-covering swimwear worn by Muslim women in public.
The southern French city of Cannes specifically banned the full-body swim outfits from its beaches on Friday, citing concerns about public order.
Last month, Cannes Mayor David Lisnard said beach access would be denied to anyone "lacking correct attire," or who was not "respectful of good customs and secularism."
Sefen Guez Guez, a lawyer for the Collective Against Islamophobia in France, said he would appeal the judge's ruling on Saturday to the Council of State, the country's highest administrative body.
The burkini ban says swimwear "manifesting religious affiliation in an ostentatious way, while France and its religious sites are currently the target of terrorist attacks, could create risks of trouble to public order."
Anyone caught flouting the rule, which is in effect through August 31, could be fined about $42.
A private waterpark near the Mediterranean port city of Marseille earlier this week canceled a burkini-only day after being criticized for the event.
France is on high alert following a series of violent incidents, including a truck attack on July 14 in Nice, adjacent to Cannes, killed 85 people. The Islamic State group claimed responsibility for the bloodshed in Nice, and less than two weeks later a Roman Catholic priest in northwestern France was slashed to death while celebrating Mass, by attackers who proclaimed their allegiance to the extremist group.
France is home to one of the European Union's largest Muslim populations. In 2011 it became became the first country in Europe to bar women from wearing full-face Islamic veils in public.