I'll try to answer this as best as I can, but there should be some other folks on the sight who know this area way better than I do. I honestly don't think you'll find any private security in the Cul de Sac area. Is this where you were intending to stay (and why)? On French St. Martin the Gendarmerie have three locations I believe ... a primary location in Marigot and another in the Quarter of Orleans. Each has an emergency phone number you can call should something arise. I think there's another Gendarmerie unit that services everything in between, but I'm not sure. I saw them around in the Orient Bay area last week, so there very much is a police presence in these areas.

Personally, I would opt for Grand Case or Orient Bay over Cul de Sac if general safety is your main concern. But, I've never heard of much in the way of crime in Cul de Sac so in all likelihood I think you would be fine there. Just my opinion, so I hope this helps.