Yummy!!!

[Byron]

LOL - the more I look at this the more I am convinced it is a female garment. For one thing photos always present the front for advertising underwear/swimwear and as a piece of decoration the little embellished tricolor would be expected to be seen at the front when wearing it , and not lost down a male butt crack at the rear.
Therefore do we regard this as a woman's thong despite the photo caption "Le String"?
The explanations "lingerie feminine/maillot de bain/un simple cache-sexe" appear here:
http://dictionary.reverso.net/french-definition/string

(I can trace no definition of string as male apparel and
just to add my own little complication to the discussion I would regard a cache-sexe as
a male posing pouch (with string) as depicted in what I believe are called vintage for the
physique photos of the Fifties).