This Roman Polanski film is likely my top choice among his works, largely because he’s in the lead role as the unassuming "Trelkovsky." He's searching for a rental apartment in Paris and, despite the rather cool welcome from the concierge (Shelley Winters), the questioning by his landlord "Zy" (Melvyn Douglas), and the lack of a bathroom, he chooses to live there. From the beginning, he’s aware that the previous tenant attempted suicide by jumping out the window and remains hospitalized; consequently, he visits her and meets her friend "Stella" (Isabelle Adjani). She's quite spirited, which doesn’t blend well with his new home where a quiet, library-like atmosphere is actively promoted. Soon, he begins to suspect that his neighbors are scheming to drive him out or something even worse. He hears sounds, voices; he seems to be imagining things. Or perhaps not? His apartment is burglarized, and he worries someone will try to harm him while he sleeps. Essentially, paranoia starts to grip this man. The fact that he’s increasingly fixated on the former occupant—who has since died—doesn't help either, contributing to noticeable shifts in his often unpredictable behavior. Is any of this actually happening or is he simply losing his mind? Polanski performs admirably, as does Adjani, but it’s truly the core idea that makes the film compelling. It brought to mind "Rosemary’s Baby," not in a demonic sense, but because of the feeling of being trapped within his dwelling with hostility from everyone around him; his own personality inherently timid and vulnerable against a danger that might be genuine or possibly imagined. There are some genuinely unsettling aspects of this psychological conspiracy thriller that I felt functioned very effectively, and the two hours passed quickly as his character really does begin to get under your skin.

Source on TMDB