Snorkeling in Southern France?

Does anyone have any experience of snorkeling in the South of France? I've read that Marseilles is good in pars but I'm struggling to find a company running excursions etc.

The term for snorkeling tours is "randonnées palmées", literally, tours with web-feet. The Cassis area and also St Raphael are very good areas for snorkeling.

Here are some websites for the South of France:

https://www.sport-decouverte.com/randonnee-subaquatique.html

http://en.active-road.com/sports-outing/snorkeling/snorkeling-marseille

http://www.paradise-plongee.com/201406222928/news/randonnee-palmee-a-marseille-pointe-rouge.html

http://www.dune-world.com/snorkeling-marseille/

Just google "randonnées palmées" and then Provence or Côte d'Azur or Marseille and you will get a lot of links.