I don't know how it's in Germany but I'd imagine it to be pretty much the same as in the Netherlands: most if not all contracts will have a trial period where the contract can be terminated by both parties on the second.
This is the risk of changing a job, even more so if the new job is in another country.
edit: based on some other comments in this thread the German law on this does not seem to be the same as the Dutch laws.
This is the risk of changing a job, even more so if the new job is in another country.
edit: based on some other comments in this thread the German law on this does not seem to be the same as the Dutch laws.