So, awhile back I wrote this answer suggesting that the student council would be ideal to handle the issue, but got told that student councils have no influence/role in such matters. In general I am used to the idea that a student council and student representatives do anything where students have to be represented at a higher level (from specific studies, to the faculty level, to the university level, up to even international politics). This does not only mean being a part of the rule making process, but also making sure students aren't disadvantaged because of professors not following those rules. Now, today I came across this question and a comment (+22) on the highest voted answer warns the OP against escalation, because of retaliations against him as a student. For me that's exactly the kind of thing where I would expect the student representative to step in, he would first approach the professor in his role as student representative (not revealing the names of individual students). If the professor doesn't resolve the issue at once the student representative would know - unlike a typical students - exactly who best to approach within the institution and is best aware of all the rules and systems that are in place (and importantly if a dean for example were to ignore student complains too many times a student council is able to escalate this easily to upper university levels).
Now, it's becoming clear to me that that's not how it works in a lot of institutions as a lot of answers which I would expect to be "go to your student representative" are instead complex diplomatic answers or just "live with it" answers, so what I am trying to understand is where this model does apply (is it typical of just some western countries? Europe in general? Only our institution?). And how a student councils activities and responsibilities broadly look in different systems.