German StVO (highway code) is mental.
You might have to also fit reflectors, dynamo/lights etc etc to comply.
They have changed the laws. Battery lights are no longer reserved for sub-11 kg bicycles. Reflectors? Police tend not to be terribly stringent on enforcing reflectors but reflective sidewall tyres or even reflective rim tape do meet the requirement. The fine for missing reflectors or a bell is also relatively modest-- I think now 10 or 20 EUROs.
The law does require 2 independent working brakes-- "Fahrräder müssen 2 voneinander unabhängige Bremsen haben"-- but gives a lot of leeway into what constitutes "working". Courts have rulled that a fixed gear is a brake. This means that a single rear brake or front brake is all that is required. The law does not stipulate which but only demands redundance-- a chain or cable can, afterall, fail.