Apartment, The (1960) - Billy Wilder
C.C. Baxter, insurance clerk and only a face in a crowd of 30,000 employees, has a little problem: He can't use his own apartment. Since he once lent out his key to one of his superiors and his mistress, this custom has spread ever since. Now, different superiors from different departments take his place for their tête-à-têtes. Being promised not to be forgotten when it comes to shifts in personnel, C.C. Baxter swallows his anger - until he finds out that the mistress of Mr. Sheldrake, the company's boss, and his recent flame, Fran Kubelik, are the same person. And they are using his apartment! Although Baxter has not been forgotten personnel-wise, the attempted suicide of Fran in his very own bed makes him think.