Fortunately, with the benefit of hindsight, we can know how this story actually played out.

> On 15 April Merkel announced in a press conference that the German government had approved Böhmermann's criminal prosecution, but would abolish the respective paragraph 103 of the German penal code before 2018. Intense criticism followed the Chancellor's decision, with speculation that she decided to allow the prosecution in order to protect Germany's refugee deal with Turkey.[3] The case was dropped in October 2016.[4]

https://en.wikipedia.org/wiki/B%C3%B6hmermann_affair

Free speech in Germany is a joke.

https://www.humanityinaction.org/knowledgebase/206-you-can-s...

https://www.dw.com/en/is-it-illegal-to-call-someone-a-nazi/a...

So what happens when Germany gets a Chancellor that comes from a racial minority?

We already know the answer: they will claim that attacks on them are racially motivated (regardless of the truth) and shut them down. Plenty of examples of that sort of thing going on today outside of politics.

Probably depends on whether the attacks focus on the chancellor's race or on their policy. Criticising the government's policy is absolutely vital to a democracy. Criticising someone's skin colour is not.

Though if the target is a politician, I'd expect them to prefer to err on the side of allowing it.

they would deal with racism probably the same as obama did when he was in office and was subject to such attacks