Walter Williams (Brian Donlevy), a hardnosed, successful businessman, lives in the Bayview Apartments with his wife Irene (Helen Walker), over whom he shamelessly fawns. The apartment shows up a number of times throughout the movie.
Then ... A visitor drives up a steep hill and turns into the apartment courtyard.
... and Now, the steep hill is Sacramento Street and the apartments are the Brocklebank Apartments at 1000 Mason Street (map), former home of San Francisco's iconic Herb Caen. Another famous resident of the Brocklebank was the enigmatic Madeleine in Alfred Hitchcock's masterpiece Vertigo (seen here). The Fairmont Hotel is on the right.
Then ... When the visitor enters the lobby, we wonder if this was filmed inside the Brocklebank?
... and Now, the answer, based on the real lobby below, is no. Evidently a studio set was used but some similarities are there - in particular, the corridor with four steps leading from the lobby. There was an elevator on the right in the movie set (above) but in real life the courtyard is on the other side of this wall.
Then ... Inside the Williams' apartment, the window view behind Walter is of the Bay Bridge where it meets Yerba Buena Island (map). This again was a studio set, using a photograph to represent the view.
... and Now, the east facing windows of the Brocklebank did indeed have a view of the bridge back then, before today's Financial District urban jungle blocked it, but the angle doesn't correspond to the movie view above. That photo was taken from further north, most likely from Coit Tower on Telegraph Hill, like the recent one below.
Then ... But when we are shown this view looking down to the courtyard from another of the apartment's windows, it's the real thing.
... and Now, the same view from ground level, unchanged in 60 years but for the lamp-posts. The building kitty-korner across Mason Street is the Pacific Union Club, also featured in Vertigo as Madeleine's husband's club (see it here).
... The Brocklebank Apartments today ... This fine 1926 building is testament to the days when class informed architectural design. It was designed, as too was the nearby Huntington Hotel, by the architects Weeks and Day.