Can this bow be self-supporting?

I would say that the wall is about 17cm thick. The opening is about 2 meters wide. How do you come to the conclusion that no lintel was installed?

Back then, the arch was set up from wood and then the rest was bricked up. This way it becomes self-supporting.

I can understand that. But does that look like a typical arch from the 50s/60s to you? That’s when the house was built! And since it is a load-bearing wall, is that simply possible?

At that time, the arch was set up from wood and then the rest was bricked up. This way it becomes self-supporting.

In your scenario, would the arch or the bricks be just decorative or also load-bearing? They definitely need to go :(

As already said. The beam also carries load while being this flat. In my opinion, you can’t just break it. I would definitely consult a structural engineer. If they have the reinforcement plan, they can see whether the ceiling is supported/calculated in only one direction or both directions.

If in doubt, you’ll have to install a support beam. It’s not rocket science after all.

Have you ever drilled a hole?

No, unfortunately I will not be able to move into the house until September 1st. But I naturally wanted to gather information about such things early on.