Home financing: Buy cheaper from parents, maintain compensation

To conclude a loan agreement with the parents for 150,000 EUR, so that initially only 500,000 have to be paid. The loan would be interest-free and parts could be waived, for example within the framework of a gift or an early inheritance.

Interest-free and unlimited loans are considered gifts by the tax office (as a child, you have an exemption amount of 400,000 EUR).
If it is really supposed to be seen as a loan at first, either interest or a fixed term should be provided in the contract. If it is to be "waived" later, it is a gift at a later point in time.

It's not quite off-topic, but since this is the subject right now, here is an additional question so as not to start a new thread: Since property and house prices have effectively exploded in recent years, the 400,000 will soon be exceeded in the future. So I am proactively giving my property and house to my son (with the condition of lifelong right of residence, etc....). How is the value actually determined for the tax office? The standard value is probably not a basis, and the sale value probably should not be considered either. Due to my right of residence as a burden, the value should not be assumed as if he could sell everything immediately. This also results in the transfer and lawyer fees.

make sure that you have a usufructuary right and not just a right of residence. Otherwise, after a longer hospital stay, the house might be gone too – if the relationship with the child no longer fits. A lifelong right of reclamation is also possible (but then notary and land registry costs will apply again).

The value of the property must be determined, for which there are several methods (actual value, comparative value, income value). You get a legally secure valuation through an expert (a short appraisal for 500-1000€ is sufficient). From the value of the property, the usufruct value is then deducted. This is calculated from the net income of the property (i.e. rental income or potential rental income minus maintenance costs) multiplied by a usufruct factor, which depends on age. But sometimes it's surprisingly less than you think...

If the child is not yet of legal age, by the way, a court-appointed supplementary guardian (often a family lawyer) is required, to ensure that the child indeed received a "gift" and not just a tax optimization. For minor children, the construct with the right of reclamation does not work either.

Thanks for the answer. Hopefully the securing method (usufruct etc.) will be known to the notary, but as always, believing is good, knowing is better.
Based on your answer, I realize that it is not as easy as I had imagined.
Since a property was sold in my area, I have only recently noticed how astronomically the values here (Berlin) have risen. In itself, it is sad that all this is left to the market. What use is it if we all (hopefully) earn well, only to have it taken away from us again for basic needs (like housing).
I just want to ensure that any potential future tax burden is at least minimized.
When I think about how large real estate companies save on property transfer tax through clever behavior, which demands quite a bit from the average consumer, I do wonder what the word "citizen-friendly" really means. I have been saving for some time for two! small airplanes, but I will not manage it in this life. But that is already social criticism, which is not particularly welcome here in the forum.
The price you mentioned is already questionable for a short appraisal when I convert it to an hourly wage and believe that it shouldn’t be that complicated for an expert to take the corresponding values from some tables. But all "appraisal prices" have also gone off the normal logic.
I just needed an appraisal (car small door dent - 10cm - appraisal 400,-) When I complained about the price, I was told, what are you complaining about, the insurance pays for it.
I will research all the "xxx" values you mentioned in order to better classify them.
I have also heard that even if I were to let a family member live in my apartment without rent (if I had one ;)), the tax office sets an imaginary rent amount, even if no actual rent is paid.
Luckily, the "majority age factor" no longer applies to my son, but for any interested readers on this topic, the note is certainly interesting.
The word tax optimization always indirectly implies harm to the state. But as long as the property is continued to be inhabited by the heir after my death, I see it differently. If he then sold it and benefited from the resulting increase in value, this income could indeed be taken into account.
I will do further research... for now, thanks.
Hopefully, the "emergency case" won't occur so quickly ;)

I wanted to give an update.

Unfortunately, my parents-in-law did not get the apartment, so for now, there is no purchase of their house planned for us either.

However, to bring some order for the future, they have had the house appraised in the meantime. The value was estimated at 582K. Now at least we have some facts for the future.

Thank you for your input.