Price increase despite fixed price!

Since this forum unfortunately does not have an acceptable PM, delete, or edit function, I will not share private details publicly here.

It is not entirely clear to me:

Has the notarized contract already been concluded here?

Can this clause 313 still apply after the purchase contract has been concluded at the notary?

Is your wife Janine? Or are the GUs now all sending out the same standard letters?

I could imagine that construction companies etc. receive templates from their interest groups/representative bodies, which are now gradually being sent out to almost all construction customers. Partly perhaps also just as a precaution, in order to be able to enforce higher prices; whether justified or unjustified will presumably have to be decided by the courts.

It is not entirely clear to me: Has the notarized contract already been signed here? Can this clause 313 still apply after the purchase contract has been signed by the notary?

That is exactly what I would be very interested in as well! The contract for work was notarized with a fixed price. Can there also be price increases there? I don't think so. Just as little as with the notarized developer purchase contracts (house + land). Or is this about the separately concluded construction contracts/contracts for work? Does anyone know about this?

To my knowledge, the form of the contract does not matter.

Then the real estate transfer tax would theoretically have to be recalculated as well!? I would be very surprised if it were that simple. Then every notarial deed would be useless if anyone could just change the contract terms afterwards as they pleased and hold out their hand.