Turnkey house - early acceptance possible?

I see it similarly to 11ant.

That can work out. But then the contract amendment must be formulated watertight. You will have to pay the lawyers.
In the end, it must not give the impression that you are splitting the trade only for tax-saving reasons and not for structurally sensible considerations.
"Splitting" would probably already be problematic. If the general contractor also provides services after the advanced contract fulfillment date that were originally included in the overall trade, it will become problematic.

But as lawyers say: "It depends."
Ultimately, it depends on how exactly the tax office will examine such a constellation in the future. You won't be the only one trying to save thousands of euros.

But it could also be that it will get lost in the overall confusion.

I don’t understand this at all. What exactly do you want to achieve? I mean, I get that you want to save the 3%. But the roughest part is already paid... I estimate about 90%.

From 11/12/2020

Do you mean the mentioned 12.12.? Or do you want to save on the painting and tiling work? Regarding that:

painters and tilers might only be able to start their work around 12/12/2020.

might. The painter will first measure and might have to wait a few days/1-2 weeks if necessary. We still had to rent a construction dryer for a week to get all the moisture out. After the heating program! ... And whether the invoicing from the craftsmen will still happen this year is also a question. I do know that partial acceptance or moving in things and taking over a room counts as silent acceptance, but as far as I know, with the general contractor’s agreement, craftsmanship work is allowed. So if you had removed your electrical installations, you wouldn’t automatically have final acceptance of the house with the electrical rough-in. So what do you want to achieve with the early final acceptance? If you still have an outstanding invoice of 25,000 to the general contractor, you’re saving only 750€, for 10,000 it’s 300€. Sure, that’s still money, but I wouldn’t blindly trust that and stage a final acceptance when quite a bit is not finished yet. Just have a partial invoice created for possible painting/tiling work, that’s probably the best option.

Legally speaking, nothing has been paid yet. Only partial payments have been transferred, but the actual payment will be made only after the (final) acceptance, colloquially with 19% on top.

Yes, the 12th of December was meant, from that day tile setters and painters can work.

My goal is that after the majority of the trades have already been completed, and overall satisfactorily, I pay 16% VAT on the installment payments already transferred and 19% on the remaining outstanding part of the general contractor (approx. €20,000) as well as 19% on the painter and tile setter services (own contribution).

So it will probably come down to the actual question of whether a partial acceptance is possible if I now agree this jointly and amicably with the general contractor and then carry out the partial acceptance. Theoretically, as I understand it, I could agree to take care of the last services (doors, sanitary objects) independently, right? That this was initially not foreseen according to the contract should not stand in the way of a later amicable contractual amendment. I found the following passage on this:

"Benefit from partial services still this year
One way to still benefit from the VAT is to agree partial services with the construction company. These must be economically reasonably delimitable and include completed construction services. As a result, partial acceptances and individual invoices are possible. An agreement must be made in advance about the partial services and their separate billing.
For example, if the basement is accepted and invoiced as a separate trade before the end of December, 16 percent VAT applies, even if the ready-to-occupy house is only accepted in 2021."

An agreement must be made in advance regarding the partial services and their separate billing.

That is not the case here, is it?