A history in motion

COSTE Architectures is now entering a new chapter of its history.

A time of clarity, maturity and commitment, driven by a conviction that has become central: design with the living, build with conscience.

For more than forty years, the agency has explored architecture as an act of responsibility. From public facilities to swimming pools and aquatic centres, from pioneering projects in energy, BIM and constructive innovation, every step has nourished the same pursuit: that of accuracy, meaning and the usefulness of places.

Over time, practices evolve, viewpoints sharpen, paths become clearer.

The history of COSTE Architectures is made of transmissions, experimentations and successive transformations. It was built across several territories, several teams, several ways of working, always driven by a shared commitment to architectural quality.

From 2026 onwards, the agency enters a new cycle, more focused, more aligned, fully embraced. COSTE Architectures continues its development around the vision carried by Emmanuel Coste, while other trajectories born of this shared history follow their own course.

This page tells that trajectory as a whole:

the trajectory of an agency that has never stopped evolving, questioning its practice and reinventing itself, without ever losing sight of the essential — an architecture in the service of people, territories and the living world.

History & Journey of COSTE Architectures

The foundations Montpellier, the 1980s

The history of COSTE Architectures has its roots in the 1980s in Montpellier, under the impetus of François Coste.

Following the closure of the LOPEZ studio, where he was head of agency, he founded his own architecture practice. His activity quickly developed around large-scale projects, mainly for public clients and private developers.

In 1988, the competition won for the redevelopment of the Château-Arnoux swimming pool (Alpes-de-Haute-Provence) marked a decisive turning point: it opened the agency to the field of aquatic facilities, which would gradually become one of its areas of excellence.

In the 1990s, François Coste also pioneered an industrial-construction approach, developing with a Montpellier-based manufacturer an industrialised building system named PIAL. This experimentation laid the groundwork for what, years later, would become a strong speciality of the agency: off-site construction and innovative processes.

The emergence of a new generation — Paris, 1997

In 1996, Emmanuel Coste, winner of the Europan 4 competition, decided to settle in the Paris region. He founded Agence Coste Architectures, beginning an autonomous development in France and abroad while maintaining a close link with the historic Montpellier office.

This period marked the beginning of a two-pole dynamic:

- Paris (Houdan), an engine for innovation, experimentation and development,

- Montpellier, which gradually structured and strengthened itself.

From 1998 onwards, the Montpellier office welcomed new partners and project directors — Renaud Delplanque, André Ariotti, then Hervé Marjoux — and took charge of many projects, often initiated or supported by the Parisian office.

A reputation built on innovation and exemplarity

Driven by Emmanuel Coste's vision, from the 2000s onwards the agency built a reputation on exemplary projects, combining technical innovation, environmental responsibility and architectural quality.

Among the major milestones

2007 – La Bonne Maison, built for Yann Arthus-Bertrand as part of the television programme Vu du Ciel, marking a strong awareness around very-low-energy buildings.

2009 – Natural Positive Building, the agency's headquarters in the Yvelines, conceived as a demonstration building with a low overall ecological footprint.

2010 – La Maison Canopée, repeatedly awarded for its energy performance and its bioclimatic approach.

In the field of aquatic facilities, COSTE Architectures has become a benchmark:

Murs à Pêches Swimming Pool, Montreuil

First public swimming pool with bio-mineral water treatment, praised for its low ecological footprint and recognised among the most innovative and responsible projects worldwide.

Saint-Nazaire Aquatic Centre,

Awarded the BIM d'Or 2014, a pioneering project for its full-BIM approach and its structural innovations.

Amboise Swimming Pool

First public pool heated and treated without chlorine, illustrating the agency's commitment to user health and water quality.

The agency also explores experimental fields:

3D-printed social housing in Reims, a world first,

Multiple projects and prototypes in off-site construction,

Advanced reflections on energy, constructive sobriety and sustainable architecture.

National and international development

Over the years, COSTE Architectures has experienced significant growth.

The Paris office reached up to 25 collaborators, animated by a shared culture of innovation and environmental commitment, while supporting the development of the Montpellier office.

Projects extended well beyond mainland France

China

School complex in Chengdu

Overseas

(Martinique, French Guiana, La Réunion, New Caledonia)

Algeria

Construction of the Ben Aknoun Olympic swimming pool and several hotel studies.

This period consolidated the position of COSTE Architectures among the leading agencies in the field of public swimming pools, aquatic centres and thermal facilities.

2019: A return to the roots, an alpine grounding

In 2019, Emmanuel Coste chose to return to his roots.

He reconnected with his family roots in the Alpes-de-Haute-Provence and opened a branch of COSTE Architectures in Sisteron, at the heart of a territory of mountains, powerful landscapes and contrasting climates.

This installation marked an important step in the evolution of his practice. It allowed the agency to strengthen its presence in the Provence–Alpes–Côte d'Azur region and the alpine arc, and to develop projects in direct resonance with the territory's challenges: rehabilitation of existing buildings, constructive sobriety, bioclimatism, relationship with the ground, water and local resources.

In contact with these landscapes and this vernacular building culture, Emmanuel Coste's approach deepened. Architecture became more attentive to natural rhythms, seasons, materials and uses anchored in everyday life. This alpine settlement gradually nourished a more organic, integrative and sensitive vision, which would structure the agency's new cycle.

2023–2026: an embraced transition, a new cycle

From 2023 onwards, the orientations of the Houdan and Montpellier teams began to diverge.

Emmanuel Coste felt the need to pursue more freely a creative, experimental and committed approach, in coherence with his deep values: the living, the human, water, rehabilitation, integrative architecture.

After several attempts at overall restructuring, a considered decision became clear: from January 2026, the Montpellier team will continue its activity under a new identity, EKHOS, while COSTE Architectures refocuses around its historic Houdan office, its Sisteron branch and the vision carried by Emmanuel Coste.

This evolution is not a rupture but a respectful and constructive transition, allowing each structure to develop its own convictions, methods and projects, in continuity of a shared past that is recognised and embraced.

Today: a refocused, committed agency turned towards the future

COSTE Architectures now enters a new cycle.

An intentionally tighter agency, favouring quality over quantity, listening to places, rehabilitation of the existing, organic and bioclimatic architecture, integration of water, air and plants, and an approach attentive to the health and well-being of users.

Designing with the living, building with conscience becomes the guiding thread of a mature, demanding and deeply human architectural practice.

A shared path

Over the years, COSTE Architectures has been carried by women and men committed to a shared cause, coming from different horizons, united by the same demand for quality and the same curiosity for architecture. Every project, every competition, every realisation is the fruit of collective work, dialogues, research and shared experimentations.

The Houdan office has, at different times, brought together a numerous and committed team, whose involvement has greatly contributed to the richness and recognition of COSTE Architectures.

To all those who have taken part in this adventure — architects, urban planners, engineers, draughtsmen, interns, partners — we express sincere gratitude for their commitment, creativity and contribution to this common history.

Those who have contributed to the adventure of COSTE Architectures, over the years…

Antoine ACHART / André ARIOTTI / Rémi AUGEREAU / Adélaïde AUGUSTIN / Christine AZAIS / Sébastien BARBIERE / Cynthia BARJOT / Etienne BARTHELEMY / Valérie BAUDOT / Jacques-Paul BAUDOT / Antoine BAUGARD / Leïla BENADDA / Amélie BERNARD / Maxime BERTRAND / Olivier BLANCHET / Agnès BOISBOUVIER / Rodolphe BONNET / Anne BONNET / Catherine BONNET / Juliette BOSSE PLATIERE / Sid Ahmed BOUABDALLAH / Imane BOULJAOUI / Yann BRESSON / Camille BRETON / Céline BRIE / Benjamin CAILLERES / Hugo COLIN / Heloïse COLSON / Sam CORDIER / Jean-Pierre CROS / Anaïs DAPPE / Benoit DE BRIX / Olivier DENTAN / Sandrine DE MAGALHAES / Stéphanie DECOUX / Claire DEGEORGE / Mattéo DEL BENE / Sylvie DELBECQ / Renaud DELPLANQUE / Marion DEMAGNY / Vincent DEMIGNY / Fouad DOUBI KADMIRI / Eric DUBOIS / Grégoire DUBOURG / Laetitia FAIMALI / Olivier GARCIA BENITO / Virginie GENET / Kevin GINEL / Nicolas GROGNET / Rachel GRONDIN / Pauline GUIMBAUD / Widad HADDANE / Pierre LAINE / Claire LEBEDEL / Emma LECOMTE / Laurence LEFEVRE / Sarah LEVESQUE / Mim LIU / Frédéric MALO / Hervé MARJOUX / Sylvie MAROT / Elise MARTINEAU / Marion MICHAUT / Nathalie MOURIES-MARTIN / Imène NAOROUZ / Cheick OUANGRAOUA / Céline PAINVIN / Eve PARENT / Thibaud PARTHIOT / Thomas PERTRIAUX / Mathieu PESY / Sabrina PINARDON / Nelly PLANTIER / Stéphane PORRET / Didier PRUDHOMME / Benoit RACLE / Baudouin RAULT / Clotilde RENAULT / Frédéric RENSONNET / Gabriela RETHORE / Clara RISTORTO / Alain ROLLEY / Stéphanie ROUSSEAU / Astrid RUELLAN / Gregor SINCLAIR / Jean Pierre SIO NAN DAM / Lucette TAILLE BOIS / Pierric TRAVERS / Bernard VERPLANCKE / Nora VEVO / Afissou YESSOUFOU / Yassine YOUSSOUFI / Yang ZHOU

Henry BARDSLEY Structural Engineer RFR / Jérome DIOT MEP Engineer EGIS / Henri FARNALIER MEP Engineer / Rémy KERVADEC MEP Engineer ETHIS / Paul LIDOVE Structural Engineer / Nicolas LUTTON HQE Engineer EODD / Hervé PEREIRA Acoustician AVA / Romain RICCIOTTI Structural Engineer LRING / Sylvain ROCHET Wood Engineer TECKICEA / Matthieu SCHNELL Structural Engineer / Patrick TUAL MEP Engineer / Emmanuel WORBE MEP Engineer KATEN