Neighbor has filed an objection - experiences?

Are you already aware of what is being criticized? If not, then call the building authority; it is your project, so the authority must also provide you with information if it directly affects you. Did the neighbors sign your submitted plans in advance, or did you submit them without a signature? We did not want to beg a neighbor for a signature and submitted the plans signed by only 2 of 3 neighbors. They were then contacted with a deadline for a justified objection, but nothing came of it.

Afterwards, I would ask your draftsman who created the submitted plans what he might have possibly overlooked. I assume you are paying someone for this service and their expertise.

As previous speakers have already mentioned, you have raised very vague questions. Unfortunately, this does not allow for a better assessment of the situation.

The question is - is the neighbor's consent even necessary? Not every state building code provides for it, even if some people would like it that way. We, for example, have such a person here. He built "as the first" on the street 20 years ago and therefore thinks he has the right to have a say with the others, or at least to be asked.

When it comes to "diverse Punkte," they will probably be available in writing. The cheapest solution would probably be to first have a conversation with the "Angrenzer." I understand, with some people that simply doesn’t work... but have you ever actually spoken to your neighbors? They might not even know that you are building a bungalow and fear that a three-story building is being put up right in front of them and that you are raising the ground level by 2.35m.

First, try to have the conversation. It might go wrong, but then you can still take the long route through the authorities, courts, and the like.

Does the construction project usually have to be replanned?
- Does the city municipality possibly have the option to "reject" the neighbor's objections, even if they were identified and submitted by a lawyer?

It depends on the objections or the building regulations.

He was the first to build on the street 20 years ago and therefore believes he has the right to have a say in others' matters, or at least to be asked.

It can also be exactly the other way around: someone comes along and thinks that all other existing houses have no right to exist anymore because they are old and so are the residents. Only his ultimate house would be something everyone has to tolerate; after all, every “Angrenzer” (luckily still called neighbor here) should be happy to look at such a unique monument.

It's a pity that the OP says nothing about the neighbor's objections. Also nothing about the legal conditions that are the basis of the building application.

Too bad that the OP says nothing about the neighbor's objections. Also nothing about the legal conditions that are the basis of the building application.

Silence usually has more significance than any explanations.