PARIS (AP) — The mayor of Paris has strongly criticized and is threatening to cancel an upcoming festival for black feminists where four-fifths of the event space will be open exclusively to black women.

Rights groups have branded the event a step backward on race issues.

In a series of angry tweets on Sunday, Mayor Anne Hidalgo said she would call on authorities to prohibit the three-day cultural festival scheduled for July. Hidalgo said she might call for the prosecution of its organizers on grounds of discrimination.

“I firmly condemn the organization of this event in Paris (that’s) ‘forbidden to white people,'” Hidalgo wrote.

France defines itself as a country united under one common national identity, with laws against racial discrimination and to promote secularism to safeguard an ideal that began with the French Revolution.

The program for the first annual Nyansapo Festival, which is set to run July 28-30 at a Paris cultural center, states that 80 percent of the event space only will be accessible to black women.

Other sections will be open to black men and “racialized women,” and one smaller space will be open to everyone regardless of race.

Organizers hope the festival will travel around Europe in coming years and said on the event’s website that “for this first edition we have chosen to put the accent on how our resistance as an Afro-feminist movement is organized.”

Prominent French rights organization SOS Racism was among civil rights groups condemning the festival, calling it “a mistake, even an abomination, because it wallows in ethnic separation, whereas anti-racism is a movement which seeks to go beyond race.”

The International League Against Racism and Anti-Semitism (LICRA), meanwhile, called the festival a “regression” and said American civil rights icon “Rosa Parks must be turning in her grave.”

Identity politics remain a recurrent hot potato in a nation where collecting data based on religious and ethnic backgrounds is banned and the wearing of religious symbols — such as the full Islamic veil — in public is prohibited.

This approach, known to the French as “anti-communitarianism,” aims to celebrate all French citizens regardless of their community affiliations.

Last week, several women attempting to stage a “burkini party” were detained in Cannes after a ban against the full-body beachwear favored by some Muslim women was upheld in a fresh decree.

The “‘burkini” event was to highlight anger against the ban, which is part of a French secular law that bans the wearing of headscarves and other religious clothing in public areas.