Work / Additional freelance work in Poland - ZUS, taxes? [11]

Hi,

Currently I am working already full time for a company (umowa o prace), but also I will be doing some freelance translation work next to that.

The company I do that for told me I would have to pay the taxes in Poland myself as this is a foreign based company.

How does this work exactly? Should I for freelance work pay additionally ZUS or just the 19%/32% income tax?

Thank you.