In which case do I need a flight permit before the start?
You do not need a flight permission for drones, if they
- fly under the open category of the EU drone regulation
- have a take-off weight of under 25 kg
- fly within sight range and
- in a height of max. 120 m.
You also do not need a permission for a night flight anymore.
Not permitted without prior authorization: flying over crowds, power stations or hospitals on and near airports and local no-fly areas.
More about the drone regulation 2021 and the LuftVG § 43 (German air traffic act)