From her signature crescent moon-print activewear to her upcycled couture, Marine Serre has proven to be both a practical and wildly inventive designer. Sustainability is at the core of her sleek, forward-thinking creations, which for Spring include dresses made from carpeting and jackets crafted from “regenerated” denim. Indeed, the pieces, which are new to BG this season, could not feel more of the moment. Here, the Parisian designer talks us through a few key looks.