So, I just spoke with the city.
Parking space plus garage may have a maximum length of 15m if it is on the border.
The wall may have an average height of 3m.
The forest area must not exceed 25m².
However, the parking space MUST be 5m long, meaning the garage can only start at 5mcm.
Our house starts at 4.70m. So, a flush garage is out of the question, hopefully the offset won’t look too bad. :-(
She also asked if a garden house already exists. Apparently, they also count that towards these 15m... Well, they are slowly going crazy XD XD XD