Except for preparing financial statements, Polish law obliges selected units to additional reporting obligations, in particular reports are to be filed with the National Bank of Poland (NBP).
This PDF explains everything in English.
Most information can be found here in Polish, along with some English. Limited information can be found here in English.
Information on the reporting to the Central Statistical Office: www.stat.gov.pl
You can also source more information about bookkeeping rules here.