Strange question...

I think you should go on TripAdvisor.com France forums there are more locals on them that likely will be able to give specific information you require. Good luck.

Alex your statement " a lot of people go there for sex"

Do you know that for a fact, since naturists do not generally go to such resorts for sex , so you are saying this place is an exception? Or are you someone who has never really been in the naturist lifestyle and like to giggle about it behind your hands and assume you know what goes on at such resorts.?

Oh I got it ,, you just went to "see it" were you one of the looky
Lou's who found it exciting?

A simple Internet search for France and naturism will turn up plenty of links to French beaches and resorts, on both the Atlantic and Mediterranean coasts. It is a well developed industry. "Campgrounds" in France can be far from roughing it, with stores and swimming pools and other services, and not a lot of elbow room.
The Cape d'Agde naturism quarter is huge, offering several hotel and holiday apartment buildings and a large campground. One section has become known for swingers but there is plenty of sandy beach where others, probably the majority of the residents, can do what they want.
Years ago, single males were permitted and were expected to purchase a licence, essentially a membership. I bought mine at the campground gate but you would be wise to research more up-to-date information on the regulations.

Thank you everyone for your comments / thoughts. I had heard the negative about Cap D'agde, and that is NOT what I'm looking for. I'll check out the other suggestions mentioned above.

An appropriate answer in the first place would have been appreciated instead of trying to show off. By the way Pat has French nationality. LOL.

I fail to see where Alex was "trying to show off". Pat had suggested the OP ask his question on the TripAdvisor forums to get some perspective from actual French citizens who might live near these resorts, and then Alex (who lives 50km from a large, well-known French resort) answered the question. Anyone who lives near a coastal area is generally going to have some insight as to the reputation of a particular beach. Having lived and worked at various points in both coastal New England as well as the Jersey Shore, if someone inquired about the suitability of some beaches for the type of vacation they were interested in, I could pretty much list which cater to families, to young singles/party-crowd, to the GLBT crowd, which were once nude beaches, which (quietly) still welcome the "clothing optional" beach-goer, etc. etc. It's not showing off if you are offering some local perspective and clearly the OP was glad to hear Alex's perspective as it confirmed some things he had already heard about this particular resort. But if someone felt Alex was just "showing off", then instead of grilling him asking him where he was getting his information from, all it really takes is a quick look at the reviews of said resort on TripAdvisor. Many confirm Alex's "lot of sex" comment is accurate, it applies to certain sections of that beach and, oh yeah, ironically, the swingers themselves are a little creeped out by single guys being "looky Lou's" as Pat calls them. So if the OP was actually interested in that resort (he's not), it would probably be good information for him to know in advance as he's questioning whether single men are going to feel welcomed, or if it is more of a couples-only environment.