Building authority wants site inspection

An inspection is not up for discussion at the moment. At least not without clear legal requirements.

§61 (6) Construction Code NRW:
The persons entrusted with the enforcement of this law are authorized, in the exercise of their office, to enter properties and structural facilities including apartments. The fundamental right to the inviolability of the home (Article 13 of the Basic Law) is restricted to that extent.

However, I would also refuse the "on-site appointment" on the grounds that the proof of factual necessity has not been provided.

Proof is not necessary here, since the original poster has not complied with the orders already issued.

They do not know what was approved and completed, how and when.

Possible, but very unlikely. When I read between your lines, I come to the same conclusion as Nordlys:

....this smells fishy to me.

How can it be that your approved construction project was accepted if it is not even finished? My theory, and probably also that of the building authority: You continued building after the completion of the first construction phase without permission. They want to take a look at that, of course you don’t want that. On Friday you will probably still be able to prevent entry to your property, but then a short-term appointment will be scheduled (certainly not 4 months later), which will then be enforced following the procedure described by Dirk.

...and when the matter is settled, meaning the building authority has conducted the inspection, then someone is sitting there with a printout of [Art. 13] in hand, a prematurely dismantled enclosure, and is happy that they insisted on their right, come what may.

and is glad that he insisted on his right,

Hello Mike29

it is interesting to see how little you are mindful of your fundamental rights. This ignorance has already led Germany to disaster once. I think you would even let a camera be installed in your bedroom. You have nothing to hide anyway.

Steven

Nonsense... Fundamental rights may be restricted under the conditions of the rule of law and that is obviously given in the first place. It could at most fail on proportionality, which cannot be assessed here.. So as I said: pursue legal remedies. That is also a fundamental right..

Nonsense... Fundamental rights may be restricted under constitutional conditions and that is obviously given in the first place.

Hello Joedreck

and this is exactly what I doubt. So far, no legal basis has been named. Yes, no administrative act has been issued up to now either.
Undoubtedly, the administrative act will come. Of course, I will have it reviewed by a specialist lawyer for construction law. If everything is flawless, I will let the building authority onto my property. But not before.

Steven

§61 (6) BauONW:
The persons entrusted with the enforcement of this law are authorized, in the exercise of their office, to enter properties and structural facilities, including apartments. The fundamental right to the inviolability of the home (Article 13 of the Basic Law) is restricted to this extent.

So far, no legal basis has been mentioned

It probably means selective reading is your problem