Private flights in Germany may be done by DMO customers according to the association rules of the Deutscher Modellflieger Verband e. V., DMFV in short. Further information: The guidelines for flying according to the DMFV rules can be found here (german).
What does this mean?
The association training certificate (https://kenntnisnachweisonline.dmfv.aero/en/, costs 25 € plus VAT) is required for the operation of drones/model aircraft with a maximum take-off mass exceeding 2 kg or at a flight altitude of more than 120 m. Multicopters/drones are generally limited to 120 m flight altitude, unless they are flown on approved model flying sites, which may have different ascent permission rules.
Up to 2 kg take-off weight and below 120 m flight altitude, you do not need the proof of knowledge or the EU certificate of competence. By the way, in instructor-pupil mode the pupil does not need his own proof of knowledge either.
The operation of model aircraft with a take-off mass of more than 2 kg is only permitted outside model flying areas with a horizontal distance of at least 150 m from the boundary of residential, commercial, industrial and recreational areas (such as parks, recreational parks, camping sites, open-air swimming pools, bathing beaches, etc.). Under 2 kg may be flown closer. Of course, nevertheless, special caution always applies in general when flying and respect for the privacy of your fellow human beings.
FPV flight is allowed. Up to a flight altitude of 30 meters, no airspace observer (spotter) is required. At a flight altitude of 30 meters, a spotter must stand next to the pilot who can point out any hazards that may occur and who has the aircraft in view at all times.
CAUTION: The video goggles must never be used to increase the maximum distance to the pilot. The aircraft must therefore be visible from the pilot's position at all times, even without the aid of video goggles.
Safety features such as return to home or fail-safe functions are also permitted.