Must the owner be here when I leave the apartment? May I leave the keys inside the apartment when I go?
Before your leaving, you AND the owner (or his representative) MUST check together the condition and the content of the apartment and sign the apartment condition - inventory agreement. So, the owner (or his representative) must be present and you can give him the keys back. If you leave in the very early morning, organising this check out in the evening the day before is always possible.