Interior window sills - What depth or overhang?

Let me guess, you have a not so thick stone? About 15cm?

I mean the exterior wall.

Hmm no 36.5, why?

I'm keeping my fingers crossed for you. Approach it like this: I don't want to argue now.... but rather solve this problem. For me, it is one. Let's discuss it.... in the end, there should be narrower windowsills.
Karsten

Well, with narrow stones there is simply no space to install the "usual" window sills of 20cm depth. Then it looks like it does with you.

But it seems to be due to something else if you have 36.5 as you say. Never mind. Have it corrected and that's that. A good [GÜ] will be willing to negotiate.

Yes, if necessary I will give him 100 euros for the inconvenience, I don't feel like arguing.