This isn't a question but just some tips we picked up when we visited Sete last week. If you are in Montpellier and would like to get out of town to the beach for the day or even an afternoon, it's a great choice.
It is 20 minute train ride from Montpellier for 12 Euros return. Once you are in Sete, a pretty 15-20 minute walk will take you from the train station ('Gare') to the busy port area. Another 20 along a gorgeous boardwalk, with coastal paths will bring you to some lovely sandy beachs. Anyway, as a tourist with limited time and one who wanted to see the coast, I really enjoyed the chance to get out of the city to a place so easily accessable.
I hope that helps someone out there!