Sunset Boulevard (styled in the main title on-screen as SUNSET BLVD.) is a 1950 American film noir directed and co-written by Billy Wilder, and produced and co-written by Charles Brackett. It was named after a major street that runs through Hollywood, the center of the American movie industry. The film stars William Holden as Joe Gillis, a struggling screenwriter, and Gloria Swanson as Norma Desmond, a former silent-film star who draws him into her demented fantasy world, where she dreams of making a triumphant return to the screen. Erich von Stroheim plays Max von Mayerling, her devoted butle
You can stream Sunset Boulevard (restored) (1950, BW cinematography benchmark, imdb score: 8.4) free and legally on OldReel, via the Internet Archive.
Yes — it is in the public domain and can be watched and shared freely.