Procedure for purchasing a part of a plot of land

I want to buy a part of my neighbor's garden. What steps do I need to take?

1. Agree with the neighbor
2. Hire a surveyor
3. ?
4. ?
5. ?

It would be nice if someone could explain the necessary steps to me so that the part of the property belongs to me soon.

Before coming to an agreement, that is before 1, one should obtain a site plan and check the land register to see if, for example, the property or the garden part is free of encumbrances. Then the neighbor must inquire at the building authority how much and whether he is allowed to give up anything at all, in case a floor area ratio limits the building in relation to the size of the property. After that, I would bring a trusted notary on board and ask about the rest, how he would like it.

That is already settled. He is allowed to sell it to me and it is free of encumbrances. I am interested in the procedure. Is it absolutely necessary to involve a notary? Or is a declaration from the neighbor to some authority sufficient that he transfers the piece to me?

Very complex topic.

Where is the property.

Lower Saxony and NRW have their own regulations. The notary is always necessary.
The survey may only be carried out by a publicly appointed surveyor. Make sure that he is also licensed in the federal state.

It is best to clarify everything in advance with the responsible land registry office. The survey is not cheap. Expect around 4000 euros.
The land registry office must then assign a new plot number.

After the survey, a notarized purchase contract is drawn up.

Must a notary absolutely be involved?

The property always goes into the land register with a notary.

It is probably different in every federal state, but I can tell you how it went for us (Saxony).

We agreed with a relative that we would get a piece of land from their garden. We obtained an excerpt from the land registry office and roughly marked out in the garden how we imagined it. Fortunately, there were no building encumbrances or similar issues.
After that, we contacted a surveyor. He obtained a land register excerpt and came by. He made a few proposals for the division (this was similar to ours, but thanks to his proposal, we saved costs because fewer new boundary stones had to be set).
Then the old boundary stones were searched for, the new one was marked with a stake, and then sent to the office. After the confirmation (which took a long time), there was a site inspection with the surveyor and the neighboring neighbors.
Then we had to wait for another confirmation from an office (unfortunately, I can’t remember from which one right now).
Only with this letter were we allowed to contact a notary. After the appointment with the notary, it took what felt like an eternity until we finally received the decision from the land registry office.

All in all, it took about 1 year and cost about 6,000 euros (unfortunately, we also had quite a few boundary stones).