ignorance of the law is no excuse

Translations
незнание закона не освобождает от ответственности
He was fined for illegal parking, and the judge told him that ignorance of the law is no excuse.
Его оштрафовали за незаконную парковку, и судья сказал ему, что незнание закона не освобождает от ответственности.
Definitions
This phrase means that a person cannot avoid legal responsibility for violating a law by claiming they were unaware of it. Everyone is presumed to know the law, so not knowing about a law does not exempt someone from being held accountable for breaking it.