This is exactly why Germany will never achieve widespread adoption. All the citizens wish to go and form their own cities, reinventing the wheel and duplicating effort. They should abandon all their smaller cities and focus their resources on a single city.
6 years ago there was an election and the conservative party and the mayor went to Windows (after Microsoft moved German headquarters from a suburb to the city) This year we had a new election now Green party leads the city council and they want to go back to Linux.
Now Hamburg, where the Green party also won big, wants to change as well. Hamburg is even more significant since Hamburg not only is Germany's second largest city (Berlin first, Munich third) but also a state, which means it has more tasks than a "pure" municipal administration like Munich, while Munich administration sees pride in being "largest municipal administration" in Germany.
to give an example of where that difference between hamburg and munich could come into play:
munic can not decide to put linux into its schools, because as a decision that would have to happen at the state level, that is bavaria.
but hamburg can.
so if the hamburg transition is successful, that may translate into more Free Software in schools, which will be a model for the other german states.
It's more nuanced. Munich has municipal schools and at least on administration side it can do what they want there. However curriculum is made on state level, thus if the curriculum depends on Microsoft software (explicit about Excel etc.?) They would have to comply. Also some state funding budgets, i.e. for getting a few machines, might be bound to "default configurations" thus for going Linux the city might have to pay out of its own budget ...