Polanski, who was absent from the ceremony, pleaded guilty to having sex with a 13-year-old girl in the US in 1977 but fled before sentencing. He has been a fugitive from justice ever since.
His win on Friday prompted French actress Adele Haenel, who last year said she had been sexually abused as a child by another director, to walk out, exclaiming: “Shame!”
Host of the ceremony, Florence Foresti, later posted an Instagram story with a black screen and the word: “Disgusted.”
The host took several jabs at the film during the ceremony, asking the audience not to applaud when she listed its nomination.