When Barney enters Dr. Valari's office through the window there is a cushion in middle of the couch, but when he leaves through the window the middle cushion is missing.
When Barney is climbing along the outside ledge of a building he passes several windows, both coming and going. One window is lighted in the long shots, and completely dark in the close ups.
Stock footage of the young demonstrators shown during the opening credits are flipped, as evidenced by a sign for a play titled "Le Vice et Le Virtu". This was likely done to keep the continuity of the direction of the marchers in both the long shot and close-up.