You could easily get one cut and made for you at any local graphic shop that makes custom vinyl stickers. The CC logo is particular easy to do because it's so simple.
CHANEL does not actually sell vinyl decal stickers. The only stickers that I'm aware of them having are the small (size of a quarter) white/gold circle seals they use when they wrap purchases.
^lol. I put a one of the white/gold Chanel seals on the back of my phone. It started getting dirty so I had to take it off, but it looked cool for a while lol!