When I taught a law school class for a few years, I was specifically directed to give no more than a certain percentage of As and a certain percentage of Bs. I was not required to flunk anyone, but there definitely was a firm curve in the sense of “you are competing directly against each other for the limited number of good grades.”
I didn’t like doing it, but it wasn’t my call. It definitely made the students unwilling to cooperate with each other in a course where cooperation would have been beneficial for all to learn the material better.