I suppose the silent asker confuses the terms ASL (Above See Level) and AGL (Above Ground Level). An Anafi can easily fly at an altitude of up to 4500 meters ASL and unofficially even higher. An Anafi, however, can only fly up to a height of 150 meters above the height on the takeoff spot while there is no restriction on flying at a negative height under the takeoff spot. That's how simple it is.
Fly safe, regards Leif.