> Some countries require you to list the transaction price/details, with proof of it is not within the norm; I don't know if that is required or not in Germany,

> Some countries require you to list the transaction price/details, with proof of it is not within the norm; I don't know if that is required or not in Germany, There's the real estate sales tax that's a percentage of the sale. You're also required to have a notary set up the whole procedure (to make sure that everybody gets precisely what was agreed upon, or to initiate a rollback - there's about 0 chance that somebody goes out of the transaction without getting what is theirs) who is on the hook for making sure that everything fits together.