The solution was to rename all other files and folder in the parent directory of said dir that also started with Ein e.g. by prefixing them with a 1_ and then go in the terminal type in sudo rmdir Ein and hitting tab to let the autocomplete-fuction do the rest for me.
That actually resolved the characters accordingly so that I was finally able to delete the directory with that commands.

The solution was to rename all other files and folder in the parent directory of said dir that also started with Ein e.g. by prefixing them with a 1_ and then go in the terminal type in sudo rmdir Ein and hitting tab to let the autocomplete-fuction do the rest for me.
That actually resolved the characters accordingly so that I was finally able to delete the directory with that command.