Work contract with exclusion §14/15

How can I now find out whether this contract for work can actually be terminated without any costs for us or not.

I had already explained this earlier: without costs only revoked (within the corresponding period), terminated without costs not. The revocation period will not be sufficient to still make the house cheaper in it.

It should already be signed today, since the offer for the house was made three weeks ago.

Without expressly confirmed continuation of the price guarantee from the offer, this has already been history for nine days, so any haste here would also be pointless.

Should I have it reviewed by a lawyer?

That is always recommended. P.S. regarding earlier:

Our building consultant assured us again in an e-mail that no costs will arise for us because the contract is on hold with the company until our final acceptance.

Secondly, she means (correctly) that an offer does not become a contract before its acceptance anyway. See also: And first of all, the lady can express opinions as much as she wants without proper authority (general commercial power of attorney or similar), without you being able to use this to your advantage. Of course, no costs arise for you as long as nothing happens apart from initiation talks. From the signature onwards, the revocation period starts, and very "smart" customers even shorten this by agreeing to immediate commencement of execution (e.g., including planning work). Have your lawyer shout at you as loudly as possible, asking if you really, definitely understood that you are N.O.T to sign anything hastily!

Dear thanks. I understood that I should not sign it. :) I will ask the consultant whether the sentence: "Im Falle der Ausübung des vertraglich vereinbarten Sonderkündigungsrechts entfällt die in §10d geregelte pauschale Vergütung, bzw. der pauschalierte Schadenersatz in Höhe von 10 % zugunsten von R---haus. Weitere Shadenserstzansprüche der Firma R...haus bestehen nicht. Ebenso besteht keine Abnahmeverpflichtung durch den Bauherrn." can be added. Is it true that prices were raised at the prefab house companies on May 1st? Should I not be impressed by the forecasted 30,000 euros more... Maybe another manufacturer will plan the house 50,000 cheaper for me... Are there actually such differences or is it largely uniform... Greetings!

I ask the consultant whether the sentence:
"In the event of exercising the contractually agreed special termination right, the flat-rate remuneration regulated in §10d, or the flat-rate damages amounting to 10% in favor of R---haus, shall be waived. No further claims for damages by the company R...haus exist. Likewise, there is no acceptance obligation by the client." can be added.

I already said that you can ask absolutely anyone—the doorman, the cleaning lady, or the intern—but only authorized representatives can make legally binding declarations of intent for the company.
We do not know which special termination right you are referring to here (nor do we know §10d—I suspect that you are supposed to pay the sign carrier if you terminate the construction contract?).
And NEVER draft any additional agreements as a layperson!

Is it true that prices at prefabricated house companies were raised on May 1? Should I not be impressed by the projected increase of 30,000 euros... Maybe another manufacturer will plan the house for me 50,000 cheaper...

It is true that (but not specifically on May 1, rather whenever "always very soon") prices are to be increased. In fact, the house manufacturers have fixed dates on which prices are adjusted according to inflation (if only so that salespeople have a deadline for their gold sales challenge). No one will ever build you the same house cheaper; less money means less standard everywhere. Only you can lower your expectations.

The wording is from the lawyer... he thinks that then the termination should be free of charge...

Whose lawyer? Yours?
Then you would already have taken legal advice. Otherwise, before signing, you should invest money in a specialist lawyer for a consultation. No one here in the forum can provide that.

By the way, a seller who exerts gentle pressure towards signing by mentioning a price increase would be suspicious to me. After planning was completed by an independent architect, we negotiated point by point with our general contractor for a good 6 months. We never heard the magic word "cost increase," only saw it in updated offers. However, those only appeared with changed points (both cost increases and cost decreases). Unchanged points were stable during this negotiation phase. This may not be the rule for all companies but might be found more often outside the big ones. Of course, that was during times of stable raw material prices. Unfortunately, those times are over. We only signed when everything was clarified. A premature signature can become expensive later.
But if you can’t afford the house in 4 weeks, can you afford it now?

Wouldn't you sign a contract to secure the price?

If the contract is okay, sure.

Don't you have to worry nowadays that the prices will explode?

No, they have been exploding for a while.

Do you think the company will still have to offer us a good price to keep us as customers?

With the current construction interest rates? Refreshingly, probably again soon, yes.