The Nazi-WIP Genre
A spin-off of WIP movies was the so-called "Nazi-Erotics" subgenre (aka "Nazi-porn" because some titles were re-released with hardcore inserts).
The Nazi movies cash in for about five years mainly on the italian, french and american markets, thanks to the fiercest sex and violence scenes ever made, blowing away every other "sexploitation" movie done before.
Historically speaking, the first "nazi" has been identified in the 1969 american movie "Love Camp 7", while in France, some efforts were made from notorius z-movies production company "Eurocinč" (for which Jess Franco directed some horror movies).
In Italy, genre reached a precise and "serious" identity and collocation only with Pasolini's "Salo" and Tinto Brass "Salon Kitty", which spawned in the cruelest and fiercest movies ever made.
The italian "nazi" movies are with no doubt the most extreme in the whole genre.