How high will the early repayment penalty be?

Nevertheless, I would not understand the bank, they could first demand a nice compensation from me and then "reinvest" the money at better conditions, or am I missing something?

The legislator or the Federal Court of Justice opposes that.
In the context of a sale – and at least in the case of TE that’s what it’s about – the bank has no options. There are fixed calculation schemes that must be strictly adhered to and/or can also be enforced by legal action.
In the case of a pure customer request for repayment, the bank is freer in calculating damages. Although any judge would roll their eyes at the bank if it comes up with a big figure at 1.x% interest and 3-4% investment alternatives (because the bank, no matter what, cannot prove any damage).

Thank you for the clarification and arguments! We are the last ones to complain if we get out without a prepayment penalty :)

We currently have an interest rate of about 1% and we have already received letters from the bank twice, offering to make unlimited special repayments - at no cost. Of course, we don’t do that.. So it looks like the banks would like their cheap money back.

@threadstarter If you are purchasing another property in parallel to the sale of the property, you should also possibly keep the topic of property exchange in mind to benefit from the favorable interest rate. A banker here can certainly explain this in more detail.

Brief feedback from my side: The bank confirms a prepayment penalty of €0. Only €300 fees would be incurred. No decision has been made yet. My wife and the children will definitely continue to live in the house for some time. Object exchange would of course be interesting due to the interest rates, but can I get excited about something new so quickly now? I first have to lick my wounds.

A brief feedback from my side:
No decision has been made yet. My wife and the children will definitely continue to live in the house for some time.

If you were to put the separation aside for now and sit down at a table like two business people, a sale is out of the question.

Your wife probably won’t find an apartment that cheap for herself and the children? At least two children = a 4-room apartment.

With your interest rate, about 340 monthly and repayment that you could possibly reduce if it becomes too much.

A divorce doesn’t necessarily have to happen immediately if things get tighter financially due to tax class.

Think about it calmly.