Francis Thinks Cesare was Asleep (Dramatic Irony)
When Jane tells Francis that she was abducted by Cesare, he doesn't believe her, because he thinks he was watching Cesare sleep through the night in the cabinet of Dr. Caligari. She assures him that she saw Cesare with her own eyes, but Francis cannot understand how Cesare could be in two places at once. The viewer saw Jane's abduction and so knows that Cesare was the one who did the kidnapping. This tension between what we know as a viewer and Francis' assessment that Cesare could not have done it creates a dramatic irony.
Dr. Caligari is the Asylum Director (Situational Irony)
After Francis realizes that the figure of Cesare that he watched all night was simply a puppet, Dr. Caligari makes a run for it. Francis follows him to the asylum, where he asks after "Dr. Caligari." The other doctors do not know who he is talking about, but instruct him to speak with the asylum director. When he gets to the director's office, it is revealed that the director is none other than Dr. Caligari himself. In this nightmare-like reveal, Francis' expectations are completely and horrifically reversed. While it seemed as though the asylum director might be the one to help him find Caligari, the asylum director is the malevolent Caligari.
Francis is in an Asylum (Situational Irony)
The biggest and most shocking reveal is an instance of situational irony. The entire story that Francis has been telling the old man—that is, the plot of the film—is brought into question when we realize that Francis is a patient at the mental asylum. While the beginning had made it seem as though he was a perfectly sane man telling a story, we now realize that he might be an unreliable narrator. While the viewer has taken the story at its word and believed in its validity, they must now question that belief when it is revealed that the storyteller is insane.
Francis's Image of Dr. Caligari is a Delusion (Situational Irony)
After it is revealed that Francis is in the asylum, we see him approaching the man who was Dr. Caligari in his account, who is now revealed to be the asylum director. Francis angrily accuses the director of being the murderous Dr. Caligari, but the director hardly flinches. Rather than become defensive about the fact that he is being accused of being a murderer, he takes Francis' accusations as further evidence of his insanity, as well as more information about how to treat his delusions. This is a complete reversal. While in the plot proper of the film it seems as though the asylum director is the insane character, we see now that it was actually Francis who was insane all along. The plot is much simpler than we had imagined. Francis is a delusional man who must be treated at an insane asylum.
