[necovek]

Income tax rates apply to any income from work, including contracted temporary work (including specifically "authorship works" which IT services generally fell under and which get 20% "normalized expenses", though if your actual costs are higher, you _can_ document expenses instead). Method of calculation is slightly different because of expenses and treatment of gross income, but rates are the same by law.

They are, however, not treated as employees (which have a lot of protections like minimum hourly wage, maximum working hours, maximum daily and weekly overtime hours, minimum number of paid vacation days, sick leave coverage at 60% of salary...). For freelancers, this does cause trouble with the pension fund employees not wanting to count your contributions toward your pension, but it depends heavily on who deals with processing your forms.