Your cat scratching at your furniture can not only leave you out of pocket but also very frustrated and annoyed at your cat for being such a bad little kitty. Cats need to scratch, it is something that cats instinctively do, not as you may think, in order to sharpen their claws, but to remove the old layers of their nails.
Do not punish your cat for scratching, or for anything you see as bad cat behavior. Punishment is unlikely to have any beneficial effect whatsoever. Your cat simply will not understand if you try to punish her in any way for something she has done, cats do not relate punishment to the “crime”, they are far more likely to relate the punishment to you!