Optimal height of finished floor level to street edge

Hmm, I still can't imagine it. I would go along with 10 cm higher.

Why don't you draw it again more precisely than before on graph paper. In my opinion, your OK floor slab should reach street level and be a bit higher than the city's green strip.

Ok, the floor level of the house is actually 17 cm higher than the street and almost 35 cm higher than the city's green strip,
Is my sketch really that bad?

Sorry. Didn't look carefully.

So what is your opinion now?

Build as you have drawn.