Inspectors from the Państwowa Inspekcja Pracy do not want to inspect shops on Sundays. As Polsat News reports:

Employees of the Państwowa Inspekcja Pracy who enforce the Sunday trading ban are rebelling against being regularly assigned duties on public holidays and have written to the Chief Labour Inspector about the matter. “In our view, this is contrary to legal norms,” states a communiqué from the Trade Union of Państwowa Inspekcja Pracy Employees. The regulations allow them to work on Sundays only in “exceptional situations”.

Trade union members from the Państwowa Inspekcja Pracy also point out that “people who work on weekends more often experience pain, musculoskeletal problems, insomnia and psychosomatic disorders”. Emotional exhaustion, work–home conflicts, mental disorders, hypertension and turning to alcohol also occur more frequently...

The Sunday trading ban has been in force since March. Until the end of 2018, trading will be allowed on two Sundays a month—the first and the last. In 2019, trading will be allowed on the last Sundays, while from 2020 the ban will cover all Sundays except for seven designated Sundays throughout the year. Breaking the ban is punishable by a fine of between PLN 1,000 and PLN 100,000. Persistent violations of the ban may even lead to imprisonment.