A woman wearing a Burkini joins a protest outside the French Embassy in London | Justin Tallis/AFP via Getty Images France’s highest court to rule on burkini ban Decision will determine whether mayors overstepped their authority.

PARIS — France's highest administrative court is expected to rule by Friday afternoon on whether mayors who enforced local bans on the "burkini" in several beachfront towns have overstepped their authority, or were justified in calling them a threat to public order.

The burkini bans now being enforced in more than a dozen French towns have prompted accusations of religious intolerance from abroad and triggered a minor political crisis at home, with ban-supporting Prime Minister Manuel Valls disagreeing publicly with two ministers on the subject.

On Thursday, members of France's Conseil d'État, a constitutional court that advises the state, gathered to deliberate on the bans following complaints from the Ligue des Droits de l'Homme, a human rights advocacy group, and the CCIF, an anti-Islamophobia group.

Both complaints argued that the burkini bans, which forbid garments that fail to "respect common decency and the principle of laïcité [secularism]," went against fundamental rights to move about and manifest religious beliefs.

The court's ruling will not just determine whether mayors overstepped their authority in issuing the ban order to local police, but also define the limits of their power to act on the question of religion in public life.

France has a tradition of stringent separation between church and state that goes beyond similar distinctions in Anglo-Saxon countries. The French notion of "laïcité" is stronger than "secularism" in that it confines displays of religious activity to the private sphere.

The burkini ban drew international scrutiny of the French concept — particularly images of policemen in the southern city of Nice, who ordered a Muslim woman to remove her covering outerwear on a crowded beach.

"I don't think anyone should tell women what they can and can't wear. Full stop. It's as simple as that," London Mayor Sadiq Khan told the Evening Standard.

Even within the ranks of Valls' government, the burkini bans are causing conflict.

After Education Minister Najat Vallaud-Belkacem told Europe 1 radio that the ban was "dangerous for national cohesion," the prime minister, who has supported the ban, shot back on RMC radio: "These measures were taken in the name of public order ... And the burkini is, once again, the enslavement of women."