After setting up some content types — some public, some internal. I installed the Access Control module, set up internal content not to be visible to anonymous users — but without any effect.
After some research, but without success, I realized the *Advanced* section at the bottom of the Access Control tab for each content type. And now the magic trick: Increase the weight and you are done. So I guess the build in access management was fighting the Access Control module, so it is up to you to make your favorite module stronger by giving it more weight. — I doubt this is intuitive. Additionally, it is for sure difficult to simply find the tiny little select box down there in a section, which is by default folded.