Protesters outside Thursday's opening night of Giacomo Puccini's Tosca held Ukrainian flags and signs saying "While Netrebko sings, Ukraine bleeds" and "Stop glorifying Russian aggressor culture".
Netrebko received an award from Russian President Vladimir Putin in 2008 but has not performed in Russia since its full-scale invasion of Ukraine in 2022.
Netrebko, one of the world's leading opera singers, was dropped by New York's Metropolitan Opera after Russia's invasion.
She is suing the company, saying she faced discrimination on the basis of gender and national origin.
She has continued to sing at many top houses and made her first US appearance in six years at a Palm Beach Opera recital in February.
In August, a group of British MPs and others, including former New Zealand prime minister Helen Clark, urged the Royal Ballet and Opera to cancel her appearances, her first with the company since 2019.
She is also due to perform at the London opera house in a production of Puccini's Turandot in December and give a recital in June.
The company scrapped plans for a run of the new production of Tosca in Tel Aviv in 2026 after almost 200 staff and performers objected because of Israel's conduct of the war in Gaza.
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