When the owners of high-end hotels want to make a splash, they hire celebrity fashion designers to create stylish interiors. But such collaborations weren’t always de rigueur. In 1984, Morgans commissioned the French interior designer Andrée Putman to put the hotel on the map. And she did — with style so modern and glamorous it looks as though it could have been put up yesterday.

One step into Morgans, which was recently restored, will give you a sense of Ms. Putman’s sleek, yet warm design aesthetic. So, too, will a walk through the Anne Fontaine flagship store on Madison Avenue. But if you want to see the breadth of her vision, a visit to the exhibit “Beyond Style — Andrée Putman,” at the French Cultural Services building, is a must.

Curated by Cyrille Putman, son of the designer, the exhibit brings together a number of disparate items that illustrate her 20 years of work. A few pieces sit in the ornate marble interior of the ground floor — notably a modern steamer trunk with sliding drawers, a pullout desk, and a stool, manufactured by the Italian company Poltrona Frau. Upstairs is a tiered circular structure that holds mirrors, lamps, pieces of clothing, small tables, and more.

The range of items is intended to reflect part of the design philosophy that guides her aesthetic. From the high to the low, Ms. Putman is famed for her ability to mix things up: Who else would put a black-and-white gingham blanket at the foot of a bed in a minimalist hotel room? And so, the expensive and the affordable are blended together here. “It can be a piano that costs 200,000 euros or a cup that costs 5 euros,” Mr. Putman said.

The piano was mentioned because, indeed, Ms. Putman recently designed an instrument for Pleyel, the French firm that made pianos for Chopin and Saint-Saëns. A strong presence in black lacquer, the Putman design has been dubbed “Milky Way (Voie Lactée),” due to the starry sky applied to the inside of the lid.

The artistic director of Pleyel, Arnaud Marion, sought out the collaboration in hopes of raising awareness of design within the music world. “If you see a car, you know that it is a Ferrari or a Mercedes. But if you see a piano onstage, you cannot say what brand it is,” Mr. Marion said.

This piano, however, was created not for the concert hall, but for clients who love music and interiors. “We tested the piano with several pianists to make sure the sound was right,” Mr. Marion said. “Pleyel pianos have a romantic sound. It is elegant, luminous, and voluptuous. It’s a very sensual sound.”

For this collaboration, Ms. Putman, who was a student of the instrument at the Paris Conservatory, created an unusual closure: The lid curves around in an L shape to attach to the bottom of the piano — rather than resting flat atop the instrument. A prop in a checkerboard pattern holds up the lid and, when open, the corner of the lid is exposed. The sheet-music holder also comes in a checkerboard pattern. The piano stool is covered in gray flannel, accented by small crystal balls on the sides for adjustment. Three of the eight limited edition pianos have been sold — at a price tag of $282,900. A standard model, which lacks the luxury touches such as the mother-of-pearl inlays for the stars of the Milky Way, goes for $141, 800.

The first-floor portion of the exhibit contains a display that calls out for some explanation. On the wall hang sheets of notebook paper blown up to about 4 feet wide. The writing in them is Ms. Putman’s, and it is there to represent her creative process. “She never draws. She tells a story to the design team,” Mr. Putman said.

The designer did not get her start through the benefits of a classroom setting. After her musical studies, she worked as a delivery person for a fashion magazine. But also at that time she was decorating and arranging her friends’ apartments. With enough encouragement regarding her taste and sensibility, she set up her own interior design and furniture shop, Ecart, in 1978. She later changed the name to her own: Agence Andrée Putman. Morgans was a breakthrough project in America, and since then she has designed several leading hotels, including the Landmark Mandarin Oriental in Hong Kong. Her inspiration boards for its rooms are on display here. Also on view is a wall of electronic picture frames with changing photographs, giving the viewer a peek into the Putman-designed interiors of private homes. And if there’s anything worth getting a peek at, it’s a Putman interior that is beautiful, but off-limits.

Until October 10 (972 Fifth Ave., between 78th and 79th streets, frenchculture.org..)