at which level B1/B2/C1/C2 people can handle dictation in French?

Fully agree with you. Sorry, I've been quite busy for some time, but now back to normal. Actually I started with going to any social group with the possibility to speak in French, only to discover that I cannot do it anymore It feels like my speaking skills went down to A1. When I have a goal, like go there and ask for this and that, than all is smooth but when trying to speak freely just nothing comes out of my mouth, the brain comes with thoughts I can't express verbally and I'm stuck. Oh well, this is no good

I've used iTalki a lot -- prices are quite reasonable (especially by Swiss standards) and with a stranger it's easier to get past the initial awkwardness. You could always ask to try a bit of dictation as well!