Buy part of a plot - temporarily lease back

I don't understand this: whether he sells you the disputed area or burdens it with a building encroachment easement for setback areas, it comes to the same thing for his construction: you cannot "double" claim the same area with setback requirements.

I do. For the neighbor, selling 200 m2 is better than a 20 m2 easement and a worthless sliver. As already says, a plan will probably help more here to understand what it's about.

Yes, of course there is a site plan and a development plan

So where are they?

Does this mean that if a property is designated as an industrial area (GE) according to the development plan, you cannot simply annex it to a property in a mixed-use area?

No. It means that the purpose of the development plan, to provide buildable plots, is at least partially not fulfilled by creating a non-developed mini-plot. So if a buildable area is designated for the industrial use GE, the subdivision would probably contradict this designation. However, as long as the development plan is secret, it remains a question of probability.

Would the variant proposed by 11ant of purchasing as an individual plot then be possible?

No, because the subdivision would already be illegal.

Or is it a matter of interpretation and only the municipality can provide me with information?

If you do not obtain information here, no help is possible here either.