The answers here are good especially as regards American academia where terms like micro aggression have taken root and are very much in. I'm not exactly sure about Germany, but Europe in general is much less understanding regarding these (real or perceived) slights. What you describe is certainly not mobbing (which would be bullying of an individual by a group) but might be racism (assuming you're a different race from the other student) or just general discrimination/xenophobia. It might also just be personal antipathy or misunderstanding of some kind.

Based on your description this is one student of a group who is being verbally insensitive to you. In Europe professors are usually not particularly used to dealing with interpersonal problems between students especially ones at the PHD level. They treat them as adults and expect them to be able to handle their interpersonal problems on their own unless the conduct very clearly violates social norms or threatens to be legally problematic. You don't actually specifically say what happened and so it's hard to judge, but given the way you describe your interaction with the professor so far, it is quite possible you have already been labeled a crybaby and/or problem student. I'm basing that more on how the professor reacted than what you did.

Now what to do about it. This depends a lot on the exact details. I strongly second the advice to find peers in the group and become friends in them. This allows you to have someone that can support you in any further confrontations and also to possibly get an opinion of someone else on what is going on and be able to shape that opinion to exert peer pressure on the student you are having problems with. Unless the violations are quite egregious I would strongly advise against bringing them up in the group or going over your advisors head. While this might work in the US I think in Europe it's still more likely to make problems for you than the other student especially since she's female and seems to be in good standing with the establishment.

As a side note I wrote this assuming you are yourself female, if you are actually male it's much more complex and much more likely to be problematic for you. In Europe males are still mostly expected to be able to deal with their own problems and shut up about it.

I realize this answer is probably not going to be very popular, but I think it's a much realistic take on the European situation.

The answers here are good especially as regards American academia where terms like micro aggression have taken root and are very much in. I'm not exactly sure about Germany, but Europe in general is much less understanding regarding these (real or perceived) slights. What you describe is certainly not mobbing (which would be bullying of an individual by a group) but might be racism (assuming you're a different race from the other student) or just general discrimination/xenophobia. It might also just be personal antipathy or misunderstanding of some kind.

Based on your description this is one student of a group who is being verbally insensitive to you. In Europe professors are usually not particularly used to dealing with interpersonal problems between students especially ones at the PHD level. They treat them as adults and expect them to be able to handle their interpersonal problems on their own unless the conduct very clearly violates social norms or threatens to be legally problematic. You don't actually specifically say what happened and so it's hard to judge, but given the way you describe your interaction with the professor so far, it is quite possible you have already been labeled a crybaby and/or problem student. I'm basing that more on how the professor reacted than what you did.

Now what to do about it. This depends a lot on the exact details. I strongly second the advice to find peers in the group and become friends with them. This allows you to have someone that can support you in any further confrontations and also to possibly get an opinion of someone else on what is going on and be able to shape that opinion to exert peer pressure on the student you are having problems with. Unless the violations are quite egregious I would strongly advise against bringing them up in the group or going over your advisors head. While this might work in the US I think in Europe it's still more likely to make problems for you than the other student especially since she's female and seems to be in good standing with the establishment.

As a side note I wrote this assuming you are yourself female, if you are actually male it's much more complex and much more likely to be problematic for you. In Europe males are still mostly expected to be able to deal with their own problems and shut up about it.

I realize this answer is probably not going to be very popular, but I think it's a much realistic take on the European situation.