Y/Project, the men’s and women’s label designed by Glenn Martens, is proudly avant-garde: Unisex tracksuits have wires in the seams to give arms and legs exaggerated, painterly volume; jeans can be turned into short-shorts; fabulous thigh-high boots are made in collaboration with that decidedly unfabulous early-aughts mainstay Uggs. But just because some of the clothes are challenging doesn’t mean they’re forbidding. Y/Project is an affectionate endeavor, and one dedicated to inclusion.

Martens stresses that point at his overstuffed 10th arrondissement atelier-office, which is bursting with bolts of fabric, piles of patterns, and racks of clothes that threaten to crowd out his growing team. (Martens won last year’s ANDAM prize, which came with 250,000 euros, just at the right time: A new space is coming soon.) It’s the month between men’s and women’s fashion weeks, and everyone is working nights and weekends. “Stephanie D’heygere, who does our belts and jewelry, is a good friend from school, and Emilie Meldem, who does our embroidery, is my old flatmate,” Martens says. “We schedule meetings after six so we can shift into drinks and dinner and leave work behind.” Ursina Gysi, the brand’s stylist, pops in as Martens is in midsentence. He teases her for taking cabs home from the dive bar down the road from the office—their de facto executive lounge—even though she lives around the corner. “You get drunk so easily!” he cracks.

Martens grew up in the straitlaced Belgian town of Bruges, earned a degree in interior design, and eventually turned to fashion, hoping to continue his studies in “something creative.” When he interviewed at the famed Royal Academy of Fine Arts in Antwerp, “I didn’t even know how to pronounce ‘Margiela,’ ” he admits, referring to the school’s most famous alumnus. The learning curve was steep, but Martens found inspiration in his peers. “Everybody in that school was superflamboyant. Crazy creatures! No one was the norm. I loved it.”

From left: Glenn Martens of Y/Project with website developer Annabel Fernandes, Y/Project “den mother” Frédérique Sebag, and photographer Arnaud Lajeunie. All wear Y/Project clothing and accessories. Martens wears his own shoes. Fernandes wears a Comme des Garçons Shirt shirt. Lajeunie wears his own T-shirt and shoes.

Photograph by Tim Walker. Styled by Sara Moonves

After graduation, Martens worked for the designer Bruno Pieters and consulted for companies like Hugo Boss. In 2012, he put out a minimalist line under his own name, but running an independent label from his tiny apartment burned him out. Martens was happy to take a full-time job when Y/Project hired him the following year, after the company’s founding designer, Yohann Serfaty, passed away from cancer. Martens was soon offered the top post, and he swiftly transformed the label, which had specialized in leather men’s wear, by artfully remaking everyday items like polo shirts, tracksuits, and jeans.

A third of Y/Project’s men’s and women’s collections are made up of the same pieces. Though forward-thinking, this gender-fluid approach was also born out of practicality. When Martens decided to expand into women’s wear, “we had no money, nor time,” he recalls. “So a lot of the ‘women’s wear’ was just men’s clothes styled differently. It was a necessity, and then I decided to make a statement out of it.”

Martens and his team have also purposely cast an abundance of amateur models of North African descent in their runway presentations. “Men’s fashion in Paris is so inspired by banlieue style,” says Gysi, referring to the city’s suburbs, which are largely populated by brown-skinned, working-class immigrants and their descendants. “We wanted to acknowledge the people who created it.” Some models, like Mohamed Djarrar and Redouane Hamma, whom Gysi discovered on the Paris Métro, have become part of the gang, having appeared in multiple shows and in Y/Project’s current campaign, shot by the photographer Arnaud Lajeunie, another good friend and a key creative collaborator.

Last year, Martens traveled to Bruges with Lajeunie and Gysi to photograph his friends and family—all ages and shapes—wearing Y/Project, setting a highly personal and constantly evolving template for the brand’s visual identity. “The only way to translate in an honest way all of the references that Glenn loves was to go back to his roots,” Lajeunie says. The results ranged from naturalistic street scenes starring childhood pals to Vermeer-style compositions featuring Martens’s grandparents. More recently, the series has grown to include staffers and friends, like their “den mother,” Frédérique Sebag. As if creating a document for posterity, the guerrilla-style pictures are stamped with the subjects’ names and locations. In them, everyone wears Y/Project fabulously but offhandedly, proud members of Martens’s expanding community of crazy creatures.