"Petite" is usually used in the UK to refer to a small women's clothing size. We don't often use the word to describe people. I have never seen a men's clothing section described as petite. I'm going to say no, it's not a natural sentence.
The other reason it looks wrong to me, as a French speaker, is that "petite" is the feminine form of the adjective so would not be used to describe a masculine noun (or a male person).
I agree that it doesn't suggest skinny. In the "petite" section of women's clothes shops, the emphasis is on clothes for short women. The size ranges are no different from the ranges in the rest of the shop (S/M/L/XL or size 8 to size 18) - they're just aimed at shorter women.
No, petite is almost exclusively used for women, especially women's clothing. In rare cases, you might hear someone address a boy that way but please don't go around calling grown men petite. I would take it as offensive.