Inside Hôtel Costes Spa

The collaboration between hotelier Jean-Louis Costes, co-founder of Paris’ five-star Hôtel Costes and designer Christian Liaigre, presents a contemporary vision of French sophistication that has become synonymous with the hospitality house.

They first joined forces in 2009, when Liaigre designed the restaurant La Société in Saint-Germain-des-Prés – a project that preceded his major redesign of the main Hôtel Costes properties, which began in 2015 and connected the spaces of Hôtel Costes (originally designed by Jacques Garcia in 1995), with those of Hôtel Lotti situated between rue de Castiglione and rue Saint-Honoré, and a third hotel on rue du Mont Thabor.

Despite the designer’s death in 2020, Costes has continued to collaborate with Studio Liaigre. And, at the end of 2025, their latest venture was unveiled: Hôtel Costes Spa – a temple of zen developed in partnership with Augustinus Bader skincare.

The spa is a hidden subterranean space located in the basement of the Paris hotel, segueing over 1,000sq m from a swimming pool to treatment rooms and a fitness area.

Liaigre’s signature style is evident in the capacious volumes, rigour of line and carefully chosen materials and tonalities, while the lighting scheme defining the mood of each space was developed with lighting designer Arnold Chan of Isometrix.

Enveloping materials contribute to the cocooning ambience: richly grained travertine walls and floors, smoked oak surfaces and lacquer finishes are highlighted by pools of light emanating from the floor.

At the heart of this inner sanctum is the 20-m swimming pool bejewelled with “lagoon-hued” mosaics under a coffered ceiling. Double treatment rooms open to the pool through large lacquered doors. Lagune lanterns and Emae wall sconces light the way.

There are eight treatment rooms in total, and the indulgences offered within range from signature Augustinus Bader facials, to radio frequency hand treatments and bespoke massages.