I’m just gonna quote the Wikipedia article here.
The Maicoletta used a Bosch six volt ‘pendulum’ electric starter system. When activated, instead of rotating the crankshaft, the starter used the generator coils on the shaft to rock it back and forth under the control of cams on the crankshaft. These cams closed contacts in the starter to trigger a reversing switch in the control box that changed the crankshaft direction at the end of each swing. This gives the impression of the crankshaft continually bouncing back and forwards against compression, when operated. A separate set of ignition points fired the spark plug in the forward direction only, and when this fires the mixture in the cylinder the engine starts to rotate normally, the starter is released and the normal ignition system takes over. This system was possible due to the piston port induction system of the two-stroke engine.
The advantage of this system is that the starter does not have to force the crankshaft to turn over against compression, so less power is required from the 6 volt system. Its disadvantage is the unusually large number of contacts, which can be difficult to adjust. The reversing switch contacts tend to wear out with extended use and can be very difficult to service or to have serviced, hence the scooter’s reputation for requiring roll starts later in life. The Maicoletta did not have a kick starter.
A Rube Goldbergian-solution to a problem that didn’t really exist, and could’ve been solved with a starter and bigger battery (I don’t even think the generator would’ve had to have been larger with a conventional starting system)? Yeah, that’s German engineering alright. (Edited because I brainfarted a bit on how it worked.)