Right but that's usually very low, isn't it? I mean if it's approximately a tenth of what you get paid by month and you have to pay it only once per year (which is the case for France), it doesn't really count as paying to do a PhD.

Some universities do not really fund a student. They are low but I have heard of such cases. I was surprised and I find it quite weird. I wonder if students actually take up such an option.