Eurostar Sun is a high-speed train that runs from the Netherlands directly to destinations in the South of France and back again. It stops at the following stations on Saturdays during the summer months (from the end of June to the end of August):
in the Netherlands: Amsterdam Centraal, Schiphol Airport and Rotterdam Centraal
in Belgium: Antwerpen Centraal and Brussel-Zuid/Midi
in France: Valence, Avignon, Aix-en-Provence and Marseille St. Charles
You can travel onward from there to destinations in the beautiful Alps or the renowned seaside resorts in the South of France.