KfW demands repayment of the grant due to the house contract

It is already very good that the KfW does not object to the previous contract conclusion, which from my (non-lawyer) perspective is inadmissible, but only questions (or doubts???) that the addendum was signed simultaneously with the contract. Proving this should actually not be difficult factually – unless the parties were so clumsy as not to have the documents linked together.
Helpful here is the practice that on the other contracting party's side the documents are usually scanned, transmitted, and stored, so a prima facie suspicion of later creation should later be refuted.

I understand that the KfW suspects exactly that: the addendum is of a later date and therefore subsequent; the contract was already validly concluded before the approval came. The addendum with the suspensive clause must have been part of the contract; otherwise, the applicants would have fallen into a trap and the funding would have to be reclaimed.

A lawyer is clearly necessary: the amount in dispute would already be in the regional court area, where legal representation is mandatory. Therefore, it would be unwise to pursue a procedure (or clarify before its initiation) without legal advice. A different font than in the main part of the contract does not invalidate anything but probably creates the prima facie suspicion here.

Thanks for the explanations!

They don’t have any design criteria there but simply see a prima facie suspicion that the suspensive condition might be younger than the contract. That would mean the contract was validly concluded before the approval and therefore harmful to the funding.

Thanks for the explanations in your posts!
As far as I understood, they were always occasionally at the construction company on-site anyway to review the new plans, etc. (regional construction company).
They have now also contacted the construction company and asked whether there is experience with such cases. The construction company of course confirms without hesitation that the addendum was included directly at the contract signing, so at least the construction company and the client are on the same side without concerns.

I honestly still can't explain what the KfW is doing there by criticizing the form.

So, if I were missing tens of billions of euros, I would come up with completely different ideas... I've been struggling with our tax office since yesterday, the situation is so 100% like that, you can only think that the brothers believe "come on, let's try it at 10, if it works at one, we've already gained something again..."

Please keep us updated. Yes, the KfW has such strange requirements that must urgently be complied with. I see it like

That is already very good that the KfW is not bothered by the previous conclusion of the contract, which, from my (non-lawyer) perspective, is inadmissible, but only questions (or doubts???) whether the addendum was signed at the same time as the contract.

There are certainly some who will fail upon a re-examination.

Please keep us posted. Yes, the KfW has such strange requirements that should be strictly followed. I see it like @11ant

The requirement not to use the funding for transactions entered into before the application approval is by no means strange. The purpose of the funding is NOT to promote sales for construction companies.

There are certainly some who will fail in an audit.

Only those who did not (deliberately) understand it. The KfW is not to blame for being misunderstood by prospective builders. The purpose of the funds is by no means to promote homeownership, but to increase the proportion of those apartments with which climate goals are pursued faster than legally required. The KfW is not a grandma for extra portions of chocolate.

I find that somewhat strange. What difference does it make if the contract was concluded in advance? The same building is created.

I just installed a stairlift. There were the same nonsensical requirements. If I comply with all the conditions, I get the lift about 3 months later. For that long, I carry the tenant up the stairs.

How much time is wasted on construction because of often rather strange requirements for the subsidies? As the saying goes, time is money.

@11ant I find that a bit odd. What difference does it make if the contract was concluded in advance? The same building is created.

The difference is that the funding is then "misused" in the sense of a manipulation of purpose. The purpose of the funding is to create an incentive to comply proactively with a measure aimed at achieving a climate goal. The legislator designed the funding measure (the KfW is only the technical processor) so that the influence of will by the funding money should precede the decision and not follow it. We are talking about taxpayers' money here, so the logic of the condition design follows that of the tax code. If the main purpose of the funding was A. to be a grant enabling poor people to build their own home at all, or B. to be a grant enabling financially sufficiently potent people to order extra premium square meters, and the "premature" pursuit of climate goals was merely an accepted side effect—then the situation would look different. But neither of these are the funding objectives, only intentional misunderstandings by the applicants—which is understandable, but not according to the original intent. Even with funding for a second residential unit, it is not about a training opportunity for the citizen's typical tax and insurance cheating muscle, but about bringing another climate-target-oriented residential unit into the housing market beyond the needs of one’s own SGB needs community aka family. I always say: "Dear people, hordes of economists have calculated the insurance-mathematical dosage exactly that in the vast majority of cases no wealth-increasing effect emerges for the creditors of the savings book myth." That as a landlord of this subsidized granny flat you do not have the seed for a real estate empire in your hand, you can be really sure of, as if our Uwe’s wife had calculated it (if anyone still remembers that C-Tel ad). Getting rich as a landlord with a lot size of one residential unit will surely always remain an unfulfilled dream—but just as a side note.

I just installed a stair lift. There were the same nonsensical requirements. If I meet all the conditions, I get the lift about 3 months later. So I have to carry the tenant up the stairs for that long.

A stair lift for a tenant is more a matter for health and social bureaucracy than for building ministry bureaucracy; that is a totally different service and legal pathway. Of course, the tenant can only submit the relevant applications once the need for the stair lift has already arisen. I assume you are paving a commendable path of goodwill (at the expense of your asset performance).