I believe in the middle of the beach (between Riu and Anse Marcel Beach Restaurant) there is an area where you could set up your own chairs and/or rent them, but I'm not positive about that. I also think there is a beach bar in the middle; I don't know about the quality of food.
I have spent several days at Anse Marcel Beach Restaurant and can speak definitively only to that. You need to rent chairs there even if you are eating there, and no coolers allowed. It's not an inexpensive day but worth it in my opinion.
Good luck! You will love the beach!
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