Quote From Dmitrii1:
Could anyone please help me with this question: average funding for PhD in Germany is about 1300€. And visa requirements contain about 1800€ for scientists who is invited to work by grants. So, funding is less than requirements. Does it mean that PhD students are always students in this terms (with students visa) or they always pay the difference by their own?
In Germany PhD students could be dealt from visa perspective as students which seems to me the case with stipend such as 1300 euro. I think the 1800 euro figure is when the institute wans to hire the candidate as a research assistant and he might do a PhD in the meanwhile. In this case the candidate can have a work visa.