This working paper includes a collection of case notes written by those national judges who attended the European Networking and Training for National Competition Enforcers (ENTraNCE Judges 2023). The training programme was organised by RSCAS between November 2022 and October 2023, with the financial contribution of the DG Competition of the European Commission. The case notes included in the working paper summarise judgments from different EU Member States that relate to diverse aspects of competition law enforcement. This working paper thus aims to increase the understanding of the challenges that are faced by the national judiciaries in enforcing national and EU competition in the context of the decentralised regime of competition law enforcement that was introduced by Reg. 1/2003.