This is a plaque memorializing the homosexual victims of the Nazis. It says, roughly, "fatally beaten, and fatally silenced. To the homosexual victims of Nazism." It refers to the fact that the silence and stigma surrounding the closet preventing even a general acknowledgment of these victims' existence until the 1980s, approximately.
This shows where some of the barbed wire would have been. It's on the fence surrounding the Jewish barracks.