The Blue Angel

The Blue Angel is a 1930 film directed by Josef Von Sternberg. The Blue Angel presents the tragic transformation of a man from a respectable professor to a cabaret clown, and his descent into madness. The film is considered to be the first major German sound film. The film is based on Immanuel Rath, a professor 
from a local college, who wanted to caught some of his students in the act of being in a cabaret and circulating photographs of a famous Lola-Lola.  Hoping to catch the boys at the club, Rath goes there later that evening and meets Lola herself. Consumed with desire for Lola, Rath returns to the night club the following evening, to return a pair of panties that were smuggled into his coat by one of his students, and stays the night with her. The next morning, reeling from his night of passion, Rath arrives late to school to find his classroom in chaos and the principal furious with his behavior.

Rath subsequently resigns from his position at the academy to marry Lola, but their happiness is short-lived, as they soon fritter away the teacher's meager savings and Rath is forced to take a position as a clown in Lola's cabaret troupe to pay the bills. His growing insecurities about Lola's profession as a "shared woman" eventually consume him with lust and jealousy. The troupe returns to his hometown and The Blue Angel, where he is ridiculed and berated by the patrons, the very people he himself used to deride. 

I felted so bad for Prof. Rath in the scene where he was forced to return back to Blue Angel to perform as a clown against his wishes, but agrees because of his wife Lola. While he was on stage she was being seduced by another man in front of him and she did not oblique. And he was forced to go on stage as if nobody notices what was going on around them. He was ridicule on the stage as a clown, all these makes him go temporary insane. He was restraint and put in a straight jacket. Then the director said to him "Don't worry

everything is going to be okay", which was not. He then was released from the straight jacket, and took the opportunity where Lola was performing to leave. After being humiliated, rejected, and destitute he dies in remorse clenching the desk at which he once taught. He did all of this for the love of a woman that didn't deserved him. 

I can interpret the overall meaning of the film as a struggle between love and betrayal, authority and disobedient. The love Professor Raft gave to Lola and the betrayal she gave back to him in returned. And between the authority and power of Professor Raft and disobedient of his student. And in return Professor Raft disobedient to the school authority.