At Sutton Place, Muriel has come fully into her own. The gut, the imagination, the freedom are all still there, but everything has come together into something peaceful and harmonious. One device unifies the apartment and makes the enfilade seem endless: The unlined block-printed silk curtains are identical from the library to the dining room. In the palest pink, they filter the light beautifully and lend a sense of airiness.

Indeed, her use of color here is particular. “My choices were based on fabrics I created in India while the apartment was under renovation,” she recalls. The result, in that liquid river light, is a palette of muted hues—peridot greens of varying intensity, the softest pinks, pale citrine, opalescent silver—all “very soothing,” as she puts it, chosen “to put one at ease, to be warm and uniting.”

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In a corner of the dining room, a 17th-century tondo painting by Giovanni Battista Caracciolo and a 1961 drawing by Jean Cocteau hang above a 1920s console by Axel Einar Hjorth. The 1960s ceramic table lamp wears a custom shade by Blanche Field. Walls covered in a custom block-printed silk taffeta by Brandolini.

The first room you enter is the library, where the pale sandy oak paneling was kept, forming the perfect backdrop for precious objects and furniture. One is immediately struck by how diverse and rarefied Muriel’s taste is, both mysterious and luxurious. A pair of original Madeleine Castaing tufted sofas, in a peridot silk damask by Claremont, are flanked by two Süe et Mare pendants, hung at eye level for a magical glow. There are Hella Jongerius tables and an exquisite bespoke floor lamp made by Hervé van der Straeten from antique Coromandel panels, gilt bronze, and semiprecious stones—a testament to the Vietnamese heritage that is never far from her decorating. A candy-pink 1960s Venetian mirror hangs between the windows, near a Robsjohn-Gibbings desk. On the opposite wall, a curved tufted sofa is paired with a Mattia Bonetti iridescent Smarties table and two slipper chairs upholstered in a patchwork of antique embroideries (one of her signatures).