For the past two decades, number 32 has housed Biologique Recherche’s Ambassade de la Beauté, and when the second half of the private mansion was recently offered for sale, the beauty brand jumped at the opportunity to expand its operations.

“The company has a strong French identity, so it was clear that the place would need to follow a French spirit,” says its chief executive officer, Pierre-Louis Delapalme.

Step forward French architect Joanne de Lépinay, whose project portfolio ranges from chic homes and restaurants to boutiques. Most of her designs have been for properties in France. De Lépinay has known the brand since she was a child and has used the products for years.

The design brief was simple: to reflect the company’s trademark visual identity of pure white, deep blue and gold, used since the brand was founded 35 years ago, and to create a distinctive Parisian style that would combine unmistakable French glamour with elegance, innovation and tradition.

“As a cultural property great care had to be taken in its renovation,” says the designer at the unveiling of the new structure. “When you have the chance to work in such beautiful premises I would say that the first thing for a designer is to stay a little bit in the background and to respect as far as possible all the remarkable elements.”

For de Lépinay, this meant preserving the building’s original decorative details, including its mouldings, ceiling cornices and classic Versailles-style timber floors, while emphasising the buildings’ double symmetry. The two entrances immediately adjacent to each other, however, presented something of a challenge.

De Lépinay decided the only solution would be to demolish the shared wall separating the two structures to create a large open space on the ground floor, while retaining the two identical internal staircases. The entrance, now via a pair of glass sliding doors, leads onto a generously sized reception area accommodating a hair salon, a dedicated room where therapists conduct the company’s skin assessments, and a large drawing room and bar decorated with custom-designed armchairs, a curvaceous Pierre Paulin sofa, and Jules Wabbes wall lamps.

The designer also created a series of display cabinets featuring a rare luminescent Italian white onyx and brass details, while a series of new stand-alone display units are a nod to American artist Richard Serra’s sculptural works.

Meanwhile, de Lépinay’s softening of Biologique Recherche’s traditional palette from white to soft beige and blue to a more contemporary navy adds a subtle modern touch.

The designer was also tasked with creating a new stylistic identity. “I thought that emphasising Parisian style while paying tribute to the 1970s’ spirit with travertine marble and rounded edges on the desk and the Pierre Paulin sofa, for example, was a good idea because it is the decade the brand was founded.”

Yvan and Josette Allouche, a biologist and a physiotherapist, founded Biologique Recherche about 40 years ago. In Hong Kong it has its own spa in Harbour City and its products are sold through a worldwide collaboration with The Peninsula hotel spas.

The brand is renowned for its facial treatments. To accommodate this, on the second floor, the designer introduced a series of therapy rooms, including a “Haute Couture” room featuring a boudoir and a striking suspended cluster of hand-blown spherical lights created by artisans in Limoges.

“The boudoir was a little room that you used to find next to sleeping rooms and it was dedicated to women for chatting,” Lépinay says.

Renovation of heritage buildings often reveals “surprises” that can affect the project schedule and call for aesthetic flexibility. Problems with different floor levels, for instance, meant the wooden floors had to be repaired and reinstalled. The building’s wooden ceiling beams were completely replaced.

The removal of the shared wall also called for specialist structural advice. The blend of old and new is both very French and very much Biologique Recherche,” says Delapalme. “A space has to combine the taste of an architect with the essence of the brand otherwise the place looks beautiful but it is not your place. It is a difficult but important balance.” Mission accomplished.