Specification of solid construction in the exposé is not correct - experiences

Hello,
we have bought a house built in 1920. The construction method was stated as [Massivbau] in the exposé.
The walls are probably all covered with drywall, and insulation has been applied on the outside. For us laypeople, it was therefore not apparent that it might be a different construction. Now we have removed drywall and plaster from one interior wall, and timber framing appeared underneath. According to the neighbors, the exterior walls are probably made of clay and are also very thick. Since we did not want to buy a timber-framed house, my question now is whether anything can still be done here. The contract has already been signed; payment has not yet been made.
Kindly, we have already received the key so that we can start, but now we had to realize that the renovation effort is considerably greater than planned.
Is there a chance to reduce the purchase price due to the information in the exposé because of false statement/fraud?
Or must a buyer recognize such things? The seller extensively renovated the house a few years ago; I think he was therefore aware. Insulation was applied on the outside, heating and electrical systems were installed.
Regards, Frank

In the exposé, the construction method was specified as solid construction.
[....]Now we have removed drywall and plaster from a wall in the interior and half-timbering appeared underneath. [....]
Since we did not want to buy a half-timbered house, my question now is whether anything can still be done here. The contract has already been signed, payment has not yet been made.

Stupid question:

Surely, if you didn't want to buy a half-timbered house, you talked to the seller beforehand about the condition of the house, right?

You don't buy a house from a "catalog" (exposé) without first having discussions about how it is constructed, etc.

Yes, we had talked. We had also said that we want to remove the drywall partition, to which it was responded that there is still a solid wall underneath. But I think such side conversations are not relevant and also not understandable. Therefore, I have tried to stick to the facts.

The exposé stated that the construction method was solid construction.

The exposé usually contains a lot more, mostly glossing over things. To what extent the content of exposés corresponds with reality is regularly disputed by lawyers in court.

We bought a house built in 1920.

For us laypeople, it was not apparent that it might be a different type of construction.

Only relying on the exposé, without an expert/surveyor? Brave. Those experts should have noticed this. The region and year of construction are already a clear indication of a half-timbered structure.

but now we have had to realize that the renovation effort is significantly greater than planned.

Who estimated the renovation effort? On what basis? Buying a pig in a poke?

What does the purchase contract say? Maybe "sold as seen," like with cars? I am not familiar with existing property purchase contracts but I suspect that specifications about the house are included or that the purchase contract overrides the brochure. Clay and timber framing should also be considered solid construction, right?

Exposés are not binding. There was also a court ruling by the BGH in 2015.

If you can prove that the seller was informed about the timber-framed construction method and then also prove that he did not inform you about it, you could win after a long legal process.

Best to see a SPECIALIZED LAWYER today and very quickly.