Company unions aren't permitted. But there's an element of this approach in the most recent approaches to undermining unions, where companies create groups for worker voices including ESG and DEI initiatives. I'm not saying companies doing this is necessarily bad, just being descriptive about that at least part of the motivation is to undermine union organizing, as even corporate lobbying groups describe it:
https://theintercept.com/2022/06/07/union-busting-tactics-di... https://www.levernews.com/fear-and-loathing-among-the-union-...
As far as whatever is done in Germany, I can't speak to that since it's outside my area of knowledge.