Germany had voluntary bike registration to prevent thefts, I still have an old bike with the sticker. Didn't work because the police just flat-out tells you that they will not investigate bike theft if you report a bike as stolen. You just get a copy of the report for the insurance, but they systematically refuse to do anything.

Well this sounds cool but I think the stolen bikes would be reduced to space parts very easily, which I agree is a hurdle for the thieves but still I personally wouldn't risk it.

On the other hand, if anybody has any info if this will be a thing in Germany, please let me know! It's surely better than nothing.

The registration cost 5 to 10€ which i think it's reasonable https://www.service-public.fr/particuliers/actualites/A14062

It’s why Japan has low rates of bicycle theft.