Ruling n°428 of 31 March 2021 (16-16.713) – Cour de cassation (Court of Cassation) – Social chamber- ECLI:EN:CCAS:2021:SO00428 – Validity of the E101 certificate in the context of proceedings for undeclared work (after preliminary ruling) : in the case of an E101 certificate whose validity has been confirmed by the issuing authority, the criminal conviction based on a definitive finding of fraud established in breach of European Union law is not res judicta.