The flag appeared on a university building in the heart of Greenwich Village during a graduation week event, and resembled the purple N.Y.U. banners flying on campus.
The decision came after a meeting in which a lawyer for the billionaire, Gautam Adani, made an unusual offer, according to people familiar with the matter.
Beginning in 2028, the Metropolitan Museum of Art will own the Neue’s Fifth Avenue home and the prestige collection of 20th-century Austrian and German art built by Ronald S. Lauder.
Angela Rayner, who resigned last year after paying the wrong rate of tax on an apartment purchase, said an investigation found she had not done so deliberately.