I worked as a manager at a local German company in Germany with a strong Worker's Council team. Performance Management was run through them, they had comments, the process was adapted and managers were onboarded. This is not to say that performance management doesn't suck in general (because once you start having metrics, people start gaming them and you're almost superimposing it on people's way of working), but the Worker's Council didn't block it, because at the end of the day it was neither invasive nor exploitative.
EDIT: typos.