Had Guillaume Coutheillas, the founder and creative director of AD PRO Directory firm FrenchCalifornia, not been such an eagle-eyed Instagram scroller, he and his husband would be living somewhere entirely different right now. Two years ago, the mere glimpse of a bit of molding and a sliver of a marble mantle on a friends Instagram Stories sparked enough curiosity about an unlisted West Village apartment, which he patiently waited for until it could be theirs.It looked like a mix of a little French, a little Victorian, Greek Revival, and Federal elements, but it was just this little tiny snapshot. I couldnt tell if it had a lot of natural light; I couldnt tell anything, says Coutheillas of the classic 900-square-foot flat he now shares with husband. I just saw the potential. The interior designers well-honed eye picked up on the little details that ultimately told him a lot about the 1834 building and what was originally its parlor.Eagle House, as Coutheillass building is known, has its original eagle medallion plaque showing that it was served by the 19th-century private Eagle Hose No. 2 firehouse. Also still intact: its classic West Village stoop with the metal railing for removing mud from shoes, something very few townhouses still have, says the designer of his magical building where everybody knows everybody.Growing up in Paris, Coutheillas was intimately familiar with living in a historical space, and a small one at that. But whats just so shocking is this apartment is older than the one I grew up in, he says. The small footprint posed an exciting design challenge: I could have definitely gotten something much larger with less character somewhere else, but I preferred to take this apartment. Once they did, Coutheillas set about repainting, changing all the hardware, replacing cabinets, installing window treatments, and swapping out light fixtures. The original floors, molding, and mantlesone Greek Revival, the other Federal styleall stayed, naturally.Furnishing the storied pad took a full year, he says, for one because clients always come first and, two, because everything had to be thoughtful and beautiful. Because theres only a select number of pieces that fit in this apartment, I wanted to look around and love every single object. Coutheillas sourced a high-low blend of furniture from France to the UK and Michigan to Louisiana, through dealers, galleries, Facebook Marketplace, 1stDibs, eBay, and Chelsea Flea. For the couples bed, Coutheillas designed a bespoke piece for his carpenters to build. The custom creation sits slightly higher than usual to accommodate four suitcases and countless winter coats beneath it. Its almost like designing for a boat where you dont have much space and you need storage everywhere, says the designer.