PARIS (AP) — Paris Mayor Anne Hidalgo has strongly criticized a black feminist festival in Paris that bans non-black people in large parts of the event, saying she might call for the prosecution of its organizers on grounds of discrimination.

In a series of angry tweets Sunday, Hidalgo said she will call on authorities to ban the three-day July cultural festival that she said was “forbidden to white people.”

France defines itself on its revolutionary values of uniting under one common national identity, regardless of race and religious differences, with laws to stop discrimination based on race.

The Nyansapo Festival organizers say that “we have chosen to put the accent on how our resistance as an Afro-feminist movement is organized.”

Rights groups have called it a step backward on race issues.