Interest-free loan/mortgage. Is that possible?

Hello! My husband and I are looking for a small house. Of course, we have thought about our financial possibilities and received the following offer from our parents-in-law during a conversation: Since I am still studying, they want to give me an interest-free loan for the amount of the renovation costs (about €60,000), and as soon as I earn, I will pay it back. However, my parents-in-law don't really have the money themselves - they would take out a mortgage on their (debt-free) house themselves and would of course have to service it until I have a job. (They would be willing to do that). The plan would be as follows: We buy a house and take out about €150,000 which we pay off ourselves. The €60,000 from my parents-in-law would be our equity, so to speak. My parents-in-law would not be registered in our land register or anything like that. Now the question is: Is that legally possible? Are there any tax or financing pitfalls? Of course, we don't want to do anything wrong and have problems later on. I hope someone here can help me. Best regards

Well, in any case, gift tax must be paid on the interest-free loan, because the interest not paid is a gift - unfortunately, I am not familiar with the exemption amounts... In any case, you should inform yourselves in this regard...

Yes, that should actually work. I don't really see any other problems, but I am definitely not an expert, so you should definitely consult a specialist again.