I'm giving the url for the google translation of two sites that offer the claim, to check for additional details in addition, if necessary, for checking if the claim is true or not.
This is one source:
This is another source.
Hope someone can help me with this.
No.
Apart from the evidence mentioned in the comments - neither Petra Klamm-Rothberger nor her Twitter Account are mentioned on the internet before December 4th - and the fact that the message is longer than twitter actually allows, the German Newspaper Spiegel says that this is a fake story, fabricated by a fake news site:
In unserer postfaktischen Zeit ist es schwer geworden, den Überblick zu behalten. [...] Das zeigte sich, als in den vergangenen Tagen ein erfundenes Zitat einer nichtexistenten Grünen-Politikerin namens Petra Klamm-Rothberger herumging.
[...]
Es gibt keine Grünen-Politikerin namens Petra Klamm-Rothberger, sie war vom "Mosel-Kurier" fabriziert worden.
My translation:
In times of post-truth politics, it is getting more difficult to keep an overview. The recent example of an invented quote by a non-existing politician of the Green Party named Petra Klamm-Rothberger shows this. [...]
There is no politician of the Green party named Petra Klamm-Rothberger, the "Mosel-Kurier" made her up.
