The film noir genre is notorious for being set in dark, corrupt, criminal underworlds where most characters are driven by personal gain and sexual motivations. Stories presented in film noir are primarily hardboiled crime stories about murder or theft. At the same time that film noir was popular, a set of rules governing the content of films called the Hays Code (or the Motion Picture Production Code) was in place. This code was based on ethics and norms of the time that it was created. The presence of this code made it difficult for film makers to fully portray the hardboiled stories in film noir while adhering to the provisions of the code.
The crime based plots of film noirs conflicted with the rules laid out by the Hays Code. Particularly, it was not acceptable to show violence or criminal activities in any detail. As a result, directors were forced to omit scenes from their films containing violence. This made it harder to convey the stories which were often centered around violence or other issues.
A characteristic of the film noir style is the corrupt world in which the stories take place where law enforcement and societal structure are unreliable or even corrupt. This too presents issues when confronted with the Hays Code. A very important purpose of the Hays Code was to make sure that government and law were never ridiculed or undermined by the film's story or characters' actions. A very important influence to the film noir genre was German expressionism, which was partially a byproduct of German discontent with society and government. The Hays Code would have made it very difficult to portray this discontent attitude in a film.
The motivations of characters in film noirs often conflicted with the ethics promoted by the Hays Code. A staple element of film noir is the characters' motivations which are frequently sexual or out of self interest. This included lawyers and police officers in the films. Again, this was a problem because ridiculing the law or law enforcement was prohibited by the Hays Code. Additionally, any implicit or explicit sex or sexuality was prohibited. This too inhibited fim makers in portraying the stories in film noirs.
