304As a corollary to the res judicata principle, the ne bis in idem principle ensures legal certainty and fairness; in ensuring that once the person concerned has been tried and, as the case may be, punished, that person has the certainty that he or she will not be tried again for the same offence (judgment of 3 April 2019, Powszechny Zakład Ubezpieczeń na Życie, C‑617/17, EU:C:2019:283, paragraph 33).