The 29-year-old great-granddaughter of composer Richard Wagner was loudly booed following her directorial debut.
Katharina is vying to become the guardian of Wagner's legacy
Katharina Wagner's interpretation of The Mastersingers of Nuremberg opened Germany's Bayreuth festival, which is dedicated to staging Wagner's operas.
But some fans were incensed by the seven-hour staging, which featured full frontal nudity and rewrote the plot.
"It was all so gratuitous," said one audience member. "It wasn't true to the text at all."
Roger Alier, a Spanish opera critic, said the production was "just horrible".
"I hear what they're singing and it has nothing to do with what's going on on stage," he said.
"I don't see where she's going with this."
Appearing in front of the audience after the final curtain, Wagner was jeered and booed by sections of the crowd - although just as many fans were impressed with her production.
The reaction may come as a blow to the young director, who is competing for control of her great-grandfather's legacy.
She is one of many family members vying to succeed her father, 87-year-old Wolfgang Wagner, who has been running the Bayreuth festival since 1951.
His early, experimental stagings also divided opinions.
The red-carpet production of Die Meistersinger von Nuernberg dispensed with period costumes and settings and turned the plot on its head.
German Chancellor Angela Merkel was in the audience
In the original, a young knight falls for a young noblewoman and decides to enter a singing contest to win her hand.
He is rejected by the "Master Singers" because he breaks all of their rules, but his natural talent ultimately overwhelms the stuffy inner circle.
Wednesday's production saw the hero dispense with his rebellious nature and gradually conform to the wishes of the singing group while the villain of the piece delivered a surreal musical outburst aimed at conformity in the arts world.
Some Wagner enthusiasts were won over by the bold staging, which saw the singing troupe running around the stage adorned with outsized genitalia.
"Surprisingly good," was the verdict of Carl Julius Brabant, who has been attending the Bayreuth festival since 1951. "It's really got oomph."