In 2010, Ike Udechuku and Kathryn Smith moved into a neoclassical house in the Saint-Gilles district and set out to create what Udechuku calls “a gallery of the living experience.” Several times a year, they partner with European galleries in presenting rare and choice furniture, objects, and art in their home. They live with the items they borrow—eating breakfast at a one-of-a-kind Danish dining table, sipping wine on an iconic sofa—and welcome collectors and visitors into their home to experience (and purchase) design icons in situ. “These pieces are intended by their makers to be used, not to be in a museum,” says Udechuku. Here, Smith sits on a vintage rosewood bench designed by the Swiss-born British architect Richard Seifert.

Udechuku and Smith used to work in law and finance, but they now primarily serve as design advisors, chasing down unique vintage pieces and creating “eclectic personalized looks” for clients’ homes all over Europe. Their own residence, Ampersand House, epitomizes their aesthetic and approach, but Udechuku is quick to point out that it is foremost “a place to live, work, and entertain—not a showroom or shop. It seems almost incidental that we routinely sell the pieces around us.”

The couple changes out the furnishings, objects, and artwork in their home up to three times per year, sending purchased items to collectors and returning pieces that didn’t sell to the partner gallery that loaned them. A recent exhibition, Brazilian Modern: Masters of Style, paired masterpieces of mid-century Brazilian furniture design, borrowed from the Milan gallery BE Modern, with some of the country’s most exciting contemporary art and design. On view in the soaring atrium are a jacaranda high board from the 1960s, a chrome and glass lamp from Italy, a black leather chair and footstool by Sergio Rodrigues, a Berber rug, and a pair of photographs by the Brazilian artist Luiz Braga.

The drawing room, the couple’s principal entertaining space, contains many highlights of the exhibition, including two Tonico lounge chairs by Sergio Rodrigues; a jacaranda bench by Alberto Reis; a leather-and-rosewood sling chair fabricated by Liceu de Artes e Oficios de São Paulo; and drawings by the contemporary Brazilian artist Paulo Climachauska.

“Mid-century Brazilian furniture is a revelation,” says Smith. “Many of the influential designers of this period emigrated from Europe to Brazil, seeing it as the land of the future. They encountered distinctive materials, techniques, and traditions, and through these particular circumstances evolved a coherent new school of design.”

When curating the rooms throughout their house, Udechuku and Smith mix borrowed pieces related to the temporary exhibition—such as the playful sculptural lamps crafted from found materials by Brazilian artist Rodrigo Almeida—with vintage American and European classics from their personal collection, such as a Florence Knoll sofa designed in 1954 and newly re-upholstered in a yellow Kvadrat fabric; a stack of 1955 Grand Prix chairs by Arne Jacobsen; glass pieces by Gunnel Sahlin for Kosta Boda; and a 1959 teak-framed nine-foot-long SW 50-4 sofa by Illum Wikkelsø for the Danish furniture company Søren Willadsen.

This September, Ampersand’s focus will shift to Belgium and the Netherlands, and the house will showcase select objects and furnishings made since World War II.

Located just off the entry hall, this room opens onto a lush garden. The residents commissioned the overhead light from designers Sylvain Willenz and Hubert Verstraeten. “The use of red billiard ball references Charles and Ray Eames’s Hang-It-All coat rack,” says Smith. The wall-hung light is by the contemporary São Paulo–based designers Luciana Martins and Gerson de Oliveira. The rug is a Moroccan patchwork from the 1960s; the teak-and-leather Kilin chair is by Sergio Rodrigues; and the cane-backed sofa is a student daybed designed by Hans Wegner for Getama in the 1950s.

Udechuku and Smith consider the rare rosewood-and-black-glass dining set by Joaquim Tenreiro the highlight of their Brazilian Modern exhibition. “It’s a true masterpiece, and the only piece I have felt really nervous about using,” admits Udechuku. “We are aware of only one other example in the world. The chairs have the appearance of great delicacy. We have to remind ourselves that they have supported diners for over 60 years and are still in perfect shape—so they are in fact remarkably sturdy.” The table is complemented by a pair of 1960s Saturn copper lamps by Danish designer Johannes Hammerborg. The ceramic vase with curvaceous handles was created by Estudio Manus. Of course, not everything is for sale at Ampersand House. The couple does get attached to their favorite finds. The monumental Siefert bench has become “something of a signature piece for Ampersand House,” says Udechuku, “and we are reluctant to part with it—despite some tempting offers.”