Nancy Thermal / Architectures Anne Démians

Architects: Architectures Anne Démians
Original Architect: Louis Lanternier (1909)
Area: 20,000 m² (215,280 ft²)
Year: 2023 partial opening, full reopening 2025
Construction Period: Studies 2016–2018, Construction 2020–2023
Renovation Years: 2016–2023
Photography: Cyrille Weiner
Lead Architects: Anne Démians
Chief Architect for Historic Monuments: Pierre-Antoine Gatier
Aquatic Design: Chabanne Architecture
Specialist Architect for Thermal Baths and Swimming Pools: Chabanne Et Partenaires
Client: Métropole du Grand Nancy
Delegated Client: Compagnie Européenne des Bains / Valvital
Builder: Bouygues Bâtiment Nord-Est
Developer: Linkcity, in partnership with Compagnie Européenne des Bains / Valvital Group
Operator / Maintenance: Compagnie Européenne des Bains / Valvital Group
Structural Engineer: Egis
MEP Engineer: Kéo
Façade Engineer: VP & Green
City: Nancy
Country: France

Nancy Thermal is the result of a century-long story of interrupted ambition and eventual renewal. Originally conceived by architect Louis Lanternier in 1909 as a grand thermal establishment, the project was halted by the First World War and remained unfinished, drifting through decades of partial uses before being revived. Its transformation was entrusted to Anne Démians, who, with Chabanne Architecture and heritage expert Pierre-Antoine Gatier, led a comprehensive rehabilitation and expansion from 2016 to 2023. The complex now spans 20,000 square meters and offers a diverse program: thermal medicine, spa and wellness, aquasport, and hotel accommodation. Démians’s design embraces duality by pairing Lanternier’s historic white colonnade with a contemporary black extension, creating a deliberate architectural dialogue rather than imitation. Connections to the adjacent Parc Sainte-Marie have been restored, and landscaped thermal gardens extend the public realm. Sustainability plays a central role, with the natural thermal spring serving both therapeutic and energy functions, supplemented by Nancy’s renewable district heating grid. Advanced water treatment and energy recovery strategies further reduce environmental impact. Through its careful balance of heritage preservation, architectural innovation, and ecological responsibility, Nancy Thermal reestablishes Nancy as France’s foremost urban thermal capital.

Nancy thermal / architectures anne démians

The completion of Nancy Thermal represents the resolution of an architectural chapter left unfinished for over a century. Louis Lanternier’s vision of 1909, interrupted by war in 1914, had long remained a fragment in the city’s history. Anne Démians was commissioned to complete this work, not by replicating the past but by confronting it with the present. Her design introduces a black horizontal extension as a counterpoint to Lanternier’s pale colonnaded façade, creating a deliberate contrast that emphasizes both temporal distance and architectural continuity.

This duality informs the spatial and urban strategies of the project. The restored central dome anchors a program that now accommodates four distinct yet interconnected functions: a thermal medical facility, a spa and wellness center, an aquasport complex, and a hotel residence. Circulation between these areas is choreographed with precision, aided by the site’s natural topography, which separates the flows of curators and general visitors. Transparency and permeability define the experience, with architecture opening directly toward the Parc Sainte-Marie. Outdoor pools have been repositioned to align with the Olympic basin, reinforcing the integration of landscape, water, and civic life.

Materiality underscores the project’s interplay between past and present. Lanternier’s béton-pierre façades, terrazzo floors, and ceramic details by Gentil and Bourdet have been carefully restored, while the Galerie Nord, with joinery designed by Jean Prouvé, has been reinstated. In contrast, Démians’s interventions employ glass, dark metal, and composite materials, offering structural efficiency and thermal performance. Perforated brise-soleil animates the façade with a dynamic play of shadow and light, echoing the rhythm of the neoclassical architecture without mimicking it. Inside, diffuse daylight softens transitions and creates the calming atmosphere long associated with thermal baths.

Environmental responsibility is integral to the renewal. The naturally hot thermal spring, which defines the site, now serves not only for therapeutic use but also as a primary source of heating. Supplemented by Nancy’s renewable district heating grid, heat recovery from technical systems, and advanced water filtration methods, the facility significantly reduces its environmental footprint. Seasonal pool coverings further optimize efficiency, ensuring year-round operation while lowering energy demand.

This careful negotiation of heritage and modernity extends beyond architecture into cultural reflection. Démians’s monograph Les Bains de Nancy, published in 2024, documents the project through the photography of Cyrille Weiner and Laurent Champoussin and the writing of Philippe Trétiack, offering a contemplative lens on the baths’ atmospheric qualities. In 2025, Démians presents Second Nature: Nancy Thermal at the Venice Biennale, an installation that explores the dialogue between architecture, water, and landscape, reinforcing the project’s identity as both civic infrastructure and cultural statement.

Nancy Thermal emerges as a landmark of contemporary heritage intervention. Rather than treating preservation as stasis, the project demonstrates how transformation can extend the life and relevance of historic architecture. Through a measured juxtaposition of materials, a thoughtful engagement with landscape, and a rigorous commitment to sustainability, Démians has redefined Nancy’s thermal complex as both a civic destination and a model for the future of urban restoration.