Censorship was enforced through the Motion Picture Producers and Distributors of American (MPPDA for short), a Hollywood created organization that handled industry-wide issues. This form of censorship was self-created, while local government censors across the country were actively banning films within their communities. The code served to predict the kind of content that would be banned; in this way the PCA was not some moral crackdown, but rather a response to a larger problem. Breen merely worked for MPPDA and, while an ardent catholic with strong religious objections, was not a member of groups like the Legion of Decency. The $25,000 fine was enforced not through the threat of legal action but because it was accompanied by much larger release problems. Theater owner’s associations would only allow films to be distributed if they had gotten the PCA seal of approval, so films with “inappropriate content” were simply not going to be going out to the public.
I hope this additional information is helpful to your understanding; I am getting my doctorate in Cinema and Media Studies and have done some research in this area, however, my comments can be sourced directly to the book Hollywood’s Censor: Joseph I. Breen and the Production Code Administration by Professor Thomas Doherty.