So often we are showing you unacceptable uses of trademarks. In order to present the full spectrum, here is Tom Sachs' use of the Chanel logo that would likely be deemed ok by a court if Chanel were to bring a trademark infringement lawsuit. Sachs' work, the Chanel Chainsaw (1996), is currently being displayed at The Metropolitan Museum of Art's exhibition "Regarding Warhol: Sixty Artists, Fifty Years." What's the difference between this and Nasty Gal's use of the Chanel trademark?
Essentially, the fair use defense is the difference. It seems obvious that Nasty Gal was attempting to profit from the easily recognizable trademark of the luxury design house by stamping its logo on t-shirts. Sachs, on the other hand, is offering a parody, specifically of our ideas of consumption and branding in fashion. Does it help that while Sachs' works are available for purchase, they are one of a kind? Probably. Does it help that they are serve a purpose (art/parody) aside from just being created for a purely commercial purpose? Probably. I think it also helps that he is not producing items that could potentially affect the market for Chanel products. I say "probably" and "I think" because the outcome of a fair use defense claim is notoriously decided on a case by case basis and very much depends on the facts of each specific case and the judges. But nevertheless, this is the closest I've seen to an acceptable use of the highly-policed Chanel trademark as of late.