Metropolis is a movie way ahead of its time. One might even say many of the ideas are advanced today. It is a Sci-fi silent film, released in 1927, focusing on two classes: the lower class and the upper class, and the vast differences between them. There is quite a bit of symbolism in this film, especially if you know about early Christian history (in the times of the Roman Empire) and understand portions of Norse mythology.
Fritz Lang was a director who made the audience think. The intention is to consider warnings and alternatives, to learn from history and not repeat mistakes of our ancestors. If you consider Metropolis in the context of its own time, it’s a very deep and important study.
Metropolis is not rated in the US. IMDB has a thorough write-up of warnings, though I respectfully disagree with some of the statements. As a black and white silent film, one would have to use his imagination to see through “very thin clothing,” especially with how quickly these scene pass through. That being said, these particular scenes could be skipped and still earn the observer a proper understanding of the symbolism intended.