I own the little garden on the photo, as well as an aluminum/glass greenhouse directly on the terrace.
The garden is about 500 sqf (50m2) with about 10 inches (20-25cm) of earth and, below that, there's about 6 inches (15cm) of large pebbles for draining covered with a layer of felt.
The greenhouse is about 100 sqf (9m2)
I'm planning to read as much as possible about permaculture next winter, but before that, I would love to hear a general idea of what the pros would favor in terms of plants and design in such conditions, just a general spontaneous idea.
There won't be much legal constraints as the place belongs to the family.
This is the climate https://en.wikipedia.org/wiki/Lausanne#Climate
Elevation is 1220 ft (372m)
South facing, but the building starts casting its shadow from about mid-afternoon.
Thanks in advance!