Dear Andreas
My father was a German citizen living in South Africa from the age of 21 (1952) till his death in 2003. He never renounced his German citizenship while living in South Africa until his death. I was born in South Africa and was a South African Citizen. However I moved to Namibia in 1987 and was 'forced' to renounced my South African Citizenship to became a Namibian Citizen (naturalization). My daughter is now 13 and I would like to apply for a German passport for her. The German Embassy in Windhoek said and I quote, "Your daughter Carmen-Issabella was born in 2003, when you had already long lost your German citizenship. Therefore she also cannot possess it" I never renounced my German citizenship, but will my South African citizenship. Is it thus correct that my daughter can not obtain German citizenship through her grandfather, who never lost his German citizenship?
Thanking you.
Heinrich Hellmann

https://en.wikipedia.org/wiki/German_nationality_law

I would fill up the formal application at the German embassy and have Germany check her case. Applying for a citizenship of another country (or serving in a foreign army) usually automatically makes your German citizenship go away, whether you intended it or not.

Didn't the Namibian naturalization require renunciation off all foreign citizenships? It generally has from what I recall, and that routinely impacts even citizenships not known/disclosed but held at the time of naturalization. If you did that naturalization-based renunciation after reaching the age of majority under Germany law at the time of Namibian naturalization, then you are likely to be out of luck with German citizenship claims. There may be some exceptions, as if having a claim that the procedure was done under duress; but even then this won't be an easy and cheap thing to accomplish.

I know of people who were able to keep German citizenship while obtaining another citizenship when the second citizenship was required for a job. There could also be exceptions if a wife is required to take the husband's nationality, etc.

It�s not a problem to has more than 1 citizenship as a born German. Funny enough CDU had problems with German/ Turkish citizenship, but not with German/ Russian......

It used to be the case that a German citizen could not voluntarily acquire a second citizenship except with express permission (employment-related or because of certain country particularities). This has been relaxed a little, and especially the voluntary acquisition of a further EU citizenship does not automatically invalidate German citizenship, but in this case, unless German citizenship was renounced under duress, I think it will be difficult for OP's daughter to acquire it.

A few questions come up:
1) Did the grandfather ever lost his German citizenship, for example by taking on the South African?
2) If the grandfather did not loose his German citizenship did the OP have theoretically two citizenships for example by getting the German by "blood line" from his grandfather and his South African by "being born in South Africa"
3) If the OP had two citizenships, did he loose them both when taking the Namibian?

I think the questions is if the OP's grandfather lost his german citizenship. It does not matter if he renounce it actively or not. As soon as you take a second citizenship your German citizenship is gone. There are exceptions to this but you would need to apply for such an exception before you take on the new citizenship. For example if you are German living in the United States of America and you want to get the US citizenship without giving up you German you have to apply for an exception at the German embassy beforehand.

If the grand father for example took the South African citizenship he would automatically have lost his German citizenship. If this did happen before the OP was born he would not be able to become a German citizen and neither will his daughter. In case the grandfather never took on the South African citizenship and was always a German citizen the OP could argue that he gained the German citizen ship by "blood line". What I don't know how the South African citizenship is granted. Is it by "blood line" or also by "Being born in South Africa" like you get the US citizenship when you are born in the US. If you get automatically a citizenship just by being born in a certain country you will keep your German citizenship. So if the OP got his South African citizenship by "Being born" in South Africa and he grandfather still had his German citizenship the OP would have gained the German citizenship, too.

It get's even more complicated with the fact the OP took on the Namibian citizenship and renounced his South African. If for example he had a dual citizenship due to "being born in South Africa" and by "blood line" would the taking on of the Namibian citizenship automatically cancel his German?

So there are many facts to be validated before a final answer can be given if the OP's daughter can obtain a German citizenship or not.

This is not quite right. I always depends how you obtained your other non-German citizenship.

Example one)
If you are born to German parents in a country where you get the citizenship by being born there it is not a problem. The classic is example is being born in the United States of America to German parents. This is tolerated. I think it is technically a loop hole in the system but this is my personal non-professional opinion.

Example two)
You are born in Germany to parents which immigrated obtained there German citizenship but never really gave up there original citizenship. Now the child is German and has the original citizenship. Here the German law says that the child can keep both citizenships for a certain time but has to decide (I think as soon as it turns 18) which to keep. This is the classical German/Turkish dual citizenship dilemma. The same does apply if you are born to a US and German citizen in Germany. You will be an US citizen and German but technically you need to decide when you are 18.

Not quite. If you acquired a second citizenship involuntarily, you do not have to decide which one to keep. You can have both (or more).