So, I have to say that the property I'm interested in is located in a rural area, but the advertisement states that several smaller lightweight structures could be built on it. Unfortunately, I don't know exactly what lightweight structures means here. I have an appointment with the real estate agent tomorrow and will clarify that then.
The real estate agent was referring to the 20m3 that can be built without a permit in outdoor areas. But that only applies to Baden-Württemberg and not to Hesse. I think he was mistaken. I haven’t even asked the municipality yet and am waiting for a response.