Interior plaster gypsum or lime

We also have plaster on the wall in the old building here, how can I find out what kind it is (without doing a material analysis at some technical institute somewhere)?
By the way, you can paint gypsum plaster with lime paint...

Sebastian, and why didn’t you want that or why did you choose lime-cement instead of pure lime plaster? Is lime-cement visually better than pure lime plaster? Or cheaper or more expensive?

People will not be happy with a plaster that the construction company applied quickly and cheaply if it is the wrong plaster on the right substrate and cracks appear or the plaster peels off. It is not about felt knowledge or carelessness but about a constructionally and building-physically correct application of the materials. Most companies do not give this any thought either because they only "know one plaster"; private builders have even less idea and "do not notice anything" until the damage may become severe. Just because something "is always done that way" does not mean it is always correct. There is, as is well known, a tendency toward collective error.

Did you already say

You still get cracks quickly with KZP - but they are not necessarily bad (if you know the cause).

Was however already quite a bit more expensive

Can you possibly tell me what you paid for lime plaster? Because my preferred plasterer wants €18.00/sqm net!

Unfortunately, only the surcharge - it went through the [GU] but before signing. The surcharge was about €8 /sqm - which of course only helps to a limited extent. It could be that the plastering company was very cheap and did a poor job. It could just as well be that the current company was very expensive because they have a good workload. It's hard to compare like this. I'm still satisfied because the result convinces me.

Thank you, the gypsum plaster should cost €8.5/sqm net. For the lime plaster, he wants €18.00, quite steep....