Building application - delay due to neighbor's lawsuit - experiences?

Well, the office is not Rome ex cathedra. Every citizen who is affected can challenge official decisions at the administrative court. I hope you have everything watertight and do not violate any regulation. I also hope your office has done its homework. Then his lawyer should actually advise him not to try it.

Right, don’t always immediately paint the devil on the wall. If everything is compliant, not much can happen.

The situation here was similar, everything approved, the neighbor filed an objection, since everything was lawful it was dismissed. We also knew exactly what would happen when our application was submitted, who would complain, why, etc... And of course, disputes can always arise, but that can happen anywhere and even with people who seemed friendly at first...

Since then we’ve had peace, we’re closing off in this direction (opposite side of the street, north) and that’s that.

With:

the neighbor's reasons are rather of the nature "my view (although he has his own property behind his house and nothing is being built there) and his solar system on his shed which might generate a few cents less per year (if at all).

he will not get far. What exactly does he want to present as a formal reason? That would be interesting to know first. I wouldn't give up right away, because that is his tactic.

Maybe he has no idea how much a lawyer costs nowadays and that he has to be able to pay for that first. Normal legal expenses insurance usually does not cover such cases but only traffic / job / purchase/sale of products.

Exactly. Anyone can first of all deliver great speeches and threats. Only they don't have to achieve anything actively.

well, it seems to be working if the OP is already scared now.

before anything happens, the neighbor first has to submit something somewhere. so far he has only threatened and maybe bluffed. involving a lawyer makes 0 sense at the moment since there is nothing to review. as everyone has already said correctly, it is of course crucial that you stick to every little rule. the house better be 5cm further away from the boundary than too close, etc... such people will find something and also like to walk around your property at night. best to already set up tripwires (e.g. holes that simply appear during the construction period ^^ )

best to set up stumbling traps in advance (e.g. holes that simply occur during the construction period ^^ )

But then pay attention to a 1000% correct, regulation-compliant construction site safety. Which, if someone breaks something, certainly won't help either, since the holes or similar obviously were still not properly secured.