In addition to the above suggestions, a very nice beach on the French Side is Friar's Bay (just north or Marigot). It has plenty of free parking, two different beach cafes (Kali's Bar & Icl t'es Alleur) that are both pretty good, and a good number of comfortable beach chairs with umbrellas for $20 USD. Now, it's not the most exciting beach in the world but it's quite relaxing and swimming here is pretty good overall. It's a haul to drive here from the cruise port in Philipsburg, but from PJIA just hang a left onto Rue de Hollande Road and head north thru Marigot. You can even walk the trail through the woods to Happy Bay Beach which i found to be quite enjoyable (though there are no facilities at Happy Bay). If you liked La Gallion in the past odds are you'll like Friar's Bay, too.