Are these rough construction costs market-appropriate for 160 sqm of living space?

1000 euros per sqm for the shell construction as you define it can work, but is rather tightly calculated. There will be nothing below that.

Our construction is currently nearing completion, in the northern outskirts of Hamburg. We also awarded the trades separately and had shell construction costs of 655 euros/sqm for 148 sqm of living space, however with 1.5 floors and a gable roof + captain’s gable. Outer walls made of aerated concrete and brick façade (which amounts to about 30,000 euros), inside, all partition walls are made of sand-lime brick. We are building a KfW 55 house, so we also have quite a bit of insulation. We had three offers, the most expensive was 750 euros/sqm. However, we are also building with a well-connected construction engineer, I don’t know to what extent that made a difference. In short, 1000 euros really seems high to me (I don’t know the prices around Berlin, but I don’t assume they are comparable to prices in southern Germany).

With us, the shell construction (concrete/Poroton/wooden roof truss) cost about 600€/m². 1000 must then be something very extravagant, or you are including other things. For us, it was about 1/3 of the total costs.

Oh yes, my price is Southern Germany and of course without cleaning work. It may be that Berlin is significantly cheaper, it probably is.

Are about 1000 eur/sqm for a simply constructed closed shell with a gable roof and windows

The OP is asking for a shell with roof AND windows.

So with windows and roof fully covered, it comes pretty much exactly to 1000 per sqm for us, but as already mentioned we have a brick facade, which (just checked the offer again) accounts for a large part at 34,000 euros. What a plaster facade costs in comparison, I do not know.