They are issued by the local city transport dept of the area you were caught a record is sent to Flemsburg were the national database is kept,you receive a photo of the car and driver the offence commited and the fine amount plus any points if applicable.If you are stopped by a police car then they will take the fine all cars issued with CC machines.Depentant on how fast and where the fines go from €50 to unlimited amounts including prison roughly the same as the UK.

If you were flashed on UK plates I very much doubt if you will hear anything I don´t know of anybody who has but there is always a first time.

I know the Netherlands do and there is an agreement between the German and Dutch regarding serious motoring offences.But if you get flashed in Germany with rhd and british plates you stand a 99.9% of hearing nothing for a €50 fine they do not bother ,my SIL works for the dept that develops the films and any film they come across with a UK plate they just throw away.Its different with HGV and serious offences then they go to a higher authority for a decision.Best bet is not to speed.