On Popiełuszki Street on Żoliborz in Warsaw you can try several kinds of Czech draught beer and many more bottled beer.  There are also original Czech appetizers available. The place is located near to Metro Młociny and, although the front of the building might discourage from entering, the interior effaces the not very good first impression. You can find here six different taps, one with Polish regional beer.  

Czeska Piviarnia
19/21 Ks J. Popiełuszki Street
1st floor, pavilion no. 29