2-family house: Border construction adjacent to neighbor's house about 70% more expensive!

Yes... You're right, for tax-free property transfer you have three options.

1. Shared Deal - too complicated
2. Inheritance - let's not assume that
3. Gratuitous gift

How about a fourth?

Keywords:
Acquisition from relatives (§ 3 No. 6 Real Estate Transfer Tax Act) and
Property transfers between spouses (§ 3 No. 4 Real Estate Transfer Tax Act)

But all of this requires good planning, some time, and a tax advisor.

Right, I actually know about the spouses thing too, and yeah, there was something.... acquisition by relatives, you can't remember everything ;-) In the end, it comes down to researching and a tax advisor.

Thanks for the addition. (I only have in mind what I myself need.)

I know a case where the parents of the daughter had the right of residence registered. The daughter dies, the widower finds a new woman, she moves into the house and makes the older people’s lives a living hell. But I was only told that. What became of it, I do not know.

The case somehow seems familiar to me from the press, radio, and television.
Since the right of residence has a value that cannot be sold... and the "step-daughter-in-law" was probably eager for it... only poisoning or pushing someone out remains to snatch the apartment.

There seems to be another alternative to the right of residence, something with usufruct, or something like that. In other words, the parents could rent it out instead of using it themselves. Which probably doesn’t work with the right of residence (since it is personal only).

But that’s where I’m out... Ask the notary/tax advisor/lawyer what’s possible.
Or divide according to the condominium law (WEG). And even there it can end badly.
“Life is like a box of chocolates, you never know what you’re gonna get.”

This case somehow seems familiar to me from the press, radio, and television.
Since the right of residence has a value that cannot be sold... and the "stepdaughter-in-law" was probably eager for it... only poisoning or bullying her out remains to snatch the apartment.

."

No, my father knew the seniors... it was probably less about the (un)knowledge of the new wife regarding possessions, rather about her jealousy because she could not bear that the parents of the ex-wife, the deceased, were still living under the same roof.

Anyway: there are horror stories, and those that actually exist.
Yes, like a box of chocolates: there is always a piece hidden inside that surprises [emoji2]
You can't insure everything, and the cheapest way is not necessarily the best.