You don't need to have passed high-school French class — or even know how to pronounce Être Cécile — to recognize that this witty T-shirt label is going places, fast. Since its 2013 launch, its slogan tees and sweats have become instant favorites among bloggers, editors, and celebrities. And, this season's collaboration with Man Repeller's Leandra Medine and Harper's Bazaar's Laura Brown is a clear indication that it's not about to slow down.