“I saw the house on my way out to an airport, on my way to Europe,” said 41-year-old Mr. Dangin, who speaks with an opulently French accent. “It was just on the market, or maybe not even on the market, one of those moments of luck, I suppose, in life, where you see something and it’s great.”

He said the three-floor brownstone was once a repository for salt or grain, a fact that he’s particularly keen on—because he fancies “rather unique properties” and not “conformity.” (On the other hand, as far as conforming goes, Time magazine once said: “Whatever Kate Hudson or Gwen Stefani or Nicole Kidman might look like in fact, what she looks like in Harper’s Bazaar or W is often Dangin’s doing.”)

Mr. Dangin and his new wife, Sarah, have a chic designer for their house. “I just hired Annabelle Selldorf as an architect,” he said. “She is doing the house of one of my best friends, Craig McDean, a photographer.”

“I have a match in Annabelle,” he said. “If we look at the windowsill, if one side is a quarter-inch larger than the other side, it’s painful—it expresses itself in physical pain. It’s anal retentive, I suppose, but it’s my way. My eye is trained to pick up on the slightest tonal or shape differences.”

So, Ms. Selldorf should take note that her client does not do stuffed closets, built-in cabinetry or bright colors. “Gray, I suppose, medium gray,” Mr. Dangin said when asked about the house’s décor. “Neutral gray; white tones; old barn wood flooring, that kind of distressed wood. I like plaster! I think there’s a certain noblesse to it.”

His sellers, city deeds show, are James and Jennifer Elworth. They bought the house for $5.25 million, only last year, from George Soros’ son Jonathan.