There are yellow bags (gelber sacke) that you can use, but I’ve only ever seen them in use where there’s not a separate yellow bin. When I lived in Düsseldorf, we could put the plastics and aluminium recycling in a clear, recyclable bag and place it in the yellow bin.

For the biomüll, you can see what’s accepted by the company that does your pickup (mine in HSK is Lobbe and they have a list of what they will accept in each type of waste container). Mine will be very cross if you use compostable bags. We can use paper bags and those are fine to go in the green/bio container.

Hope this helps a bit!

We have “a fish rots from the head down”, so very similar.