ᐅ Functioning of a Floor-Level Shower Drain (Older Buildings)

Hello everyone,

I’m new here, so please forgive me if anything is unclear 😀

A bit of context: I have a small old apartment in Berlin with a very old bathroom, where the shower drain regularly causes me problems.

The shower is flush with the floor, and the water flows into a trap in the floor—not in the shower itself. To be honest, I’m completely unfamiliar with this type of trap (see sketch). Could someone briefly explain what it’s called or how it works?

Best regards