The Pro Europa Christiana Federation wants the show orchestrated by Italian director Romeo Castellucci to be canceled and has launched an online petition to gather public support.
In a letter sent to the Monnaie's director and to Didier Reynders — the Belgian minister in charge of cultural affairs — the association argues that the production is "obscene and hurting Christians."
The show is set to run from Nov. 5-12.
The petition, which has gathered more than 10,000 signatures, claims that "the symbolic character of Saint Joan of Arc is again the target of a pornographic representation, this time in Brussels. An actress completely naked is meant to represent her and pushes the obscenity to a change of sex during the performance."
La Monnaie director Peter de Caluwe has been unimpressed by the criticism and said that the show will go ahead as planned. He defended Castelluci's artistic choices and said in a statement this week he was "stupefied" by the association's claims.
"As soon as all symbolism has been removed, a naked woman stands on stage," he said. "This is not a revolutionary representation of Joan of Arc. Immediately after she was put to death, paintings and statues represented her half-naked."
Co-produced with the Lyon opera house, "Joan of Arc at the Stake" was premiered in the French city two years ago, triggering protests from far-right militants who clashed with police before the last performance.
"La Monnaie is particularly committed to freedom of expression," de Caluwe said. "We respect the opinions of others, but we ask them to show the same respect to us."
End/AP/UNB/TZ