Earlier in the film, Louise receives a telegram from her father, which is addressed to her at "62 Riflestrasse". Later in the film, when James enters her apartment building, the number is clearly seen to be "37".
When James comes out of Professor Schumann's office and passes through the gate, its hinges are on the right and it opens anti-clockwise. Later, when Paul passes through the same gate, its hinges are on the left and it opens clockwise.
When Louise enters the office of Professor Schumann, the rail surrounding the secretary's space has the gate next to where Louise is standing (to the right of camera). In the next shot, the gate has shifted to where Louise is sitting (to the front of camera).