BY PLANE: The nearest airport is Perpignan (PGF). From the airport you can take a bus into Perignan before taking a train to Argelès-sur-Mer. You can then walk (20-30 minutes) to the festival or get a taxi.
BY TRAIN: Perpignan is well connected by rail across France and into Spain. From here you can reach Argelès-sur-Mer by train in around 15 minutes.