Open Questions:
- where will you get married?
I assume Luxembourg Turkey
- has the marriage process been started?
- some form of documentation of application (preferably in German) would be helpful
where in Germany (state) are you registered? Saarland
Please incorporate the answers into the original question.
Luxemburg:
Since you want to create your main residence in Luxemburg, the family reunification seems to be the best option.
Application for family reunification for third-country nationals
- the Prerequisites for the sponsor seemed to be fulfilled, since the sponsor has a BlueCard
- the applicant will have a residence permit from Germany
If the third-country national has a valid residence permit for family members of an EU citizen or a valid residence permit issued by another EU Member State, a visa is not required. The third-country national must nonetheless have a temporary authorisation to stay.
- an application for a temporary authorization should be made
- but inform them of your intention of continuing your Masters + PhD in Germany
Germany:
Inform the local Foreigners Office, that issued your residence permit, of your intention of
- getting married in
Luxemburg (with possible documentation) Turkey
- Application for family reunification in Luxemburg
- continuation your Masters + PhD in Germany
Since, I assume, your present residence permit is for studying
- your legal situation will probably not change inside Germany
- other than you are getting married and will regularly be (and have a residence) in Luxemburg
Not knowing which state you are studying in Germany makes it impossible to look up the corresponding rules which can differ in details from state to state.
The pdf Ihr Kontakt zur Ausländerbehörde in Saarbrücken lists contact numbers.
If you live in Luxemburg and study in Germany you will be a Grenzgänger
- live in one country and work/study in another, crossing regularly
There seems to be a department for that:
- Grenzgänger tel. 0681-501-7165, Room 21
I suggest calling them to ask them about this situation and make an appointment.
The final result will probably be that you will have 2 main residences
- one in each country with a corresponding residence permit
As long as both countries know beforehand what is going on, there should be no problem.
Assume that Luxembourg will be asking Germany for information about you. So informing Germany beforehand is a good idea.
How this will effect the time for eligibility for a Luxembourg permanent residence permit is a good question and difficult (if not impossible) to answer here.