Can you work on Sundays and Polish national holidays?
Generally speaking, no. There are some exceptions, like for example search and rescue actions, restaurants, hotels, transportation, hospitals. A shop owner cannot require an employee to work on Sundays or national holidays (again with some particular exceptions). Shopping malls are kept closed, but cinemas, restaurants and cafes are open.
National holidays in Poland are determined in a statute. There are 13 days counted as national holidays in a year, which is actually much more than in many European countries. Just as many Polish employees work overtime, they also love time off during holidays.
An employee who works under a particular working time schedule, referred to as the weekend working time schedule, may also work on Sundays and national holidays. Such an employee may work as long as 12 hours a day (i.e. 4 hours longer than the standard working time scheme).
A day off in lieu
Work on Sundays and national holidays is rewarded primarily by a day off in lieu. When this is not possible, an employee is entitled to an additional pay premium in the same amount as for overtime work.
An employee working on Sundays on a regular basis should have a Sunday off once in every 4 weeks.