Does the serial number and controllato number match on the authentic GUCCI?
That is supposed to be Chanel not Gucci. If you get a black controllato card (size of a business card) with a Gucci bag, then it's probably fake.
The gucci bag came with a controllato card and gucci care booklet not a black card. Do you know if the serial number on the label and the controllato card number should match on an authentic gucci?
If you post this in the "Athenticate this Gucci" thread of the Gucci forum (when you log into purse forum, scroll down and you will see a list of designers) you will probably get a little more help.