Two comments
Blarney Irish Pub
Two monthly Irish Music sessions at Blarney Irish Pub in Berlin-Kreuzberg.
Free entry, all welcome to play, sing and/or listen.
1st session: every 1st Saturday. Mixture of tunes and songs. Level: all levels, it depends on who is showing up.
2nd session: every 3rd Saturday. Level: advanced to professional.
Both sessions start at 9pm.
Re: Blarney Irish Pub
Visited this one recently when visiting Berlin. The session is there, but (at least that one time when I came) it was a singing-only session: some folks with guitars were singing generic English-language songs turn by turn. No tunes.
I was told this is not normal though, that normally some musicians who play tunes are present too. So maybe that was was a bit of bad luck.