Neighbor is building a retaining wall on my property. What should I do?

It's as easy as driving 100 km/h in a 30 zone

Hehe, I had just typed exactly the same.

Does the surveyor do that anyway in connection with the work for a new building?

The surveyor investigates the boundaries to the extent required for the construction. If the location of your house is established 3m parallel to the western boundary and with a 5m distance to the street boundary, only these two boundaries will be checked on site. If you want more, you have to express that.

For understanding, how is a radius displayed in the cadastre.

2 points and a reference point as radius?

For understanding, how is a radius displayed in the cadastre?

2 points and a reference point as a radius?

Good question. On the phone, the surveyor told me that a radius is indicated there.
I have an appointment with the surveyor in 2 weeks and will ask in detail.

The behavior of your neighbor is unacceptable. I would involve my lawyer here asap. At 800/sqm2, I would also enforce a rollback. And very important - do not give your neighbor any opportunity to attack! If you show your legal muscles, he will probably not let it go without a fight.

The unfortunate thing is that the relationship is already destroyed due to his selfishness.

I wish you strength and success! Feel free to report how you proceed from here.

This is not a tip from me, but if boundary stones are dug out, the district office has to send a surveyor. Of course, someone has to report that and dig it out beforehand

Thank you for the response. This solution is a bit too risky for me. I will try to notify the city in advance about the height of the retaining wall. Let's see what the building inspector says.