High above the town of Mareil-Marly, which is close to the metropolitan area of ​​Paris and from where the characteristic towers of the La Défense district can be seen from afar, the HEMAA Architectes studio has developed the school complex of “Les Violettes”, a kindergarten that preserves and enhances the qualities of the natural environment in which it is located.

The project is configured compactly, prioritizing the play area and natural lighting of the different spaces. For this purpose, numerous windows are incorporated in the walls that separate the classrooms from the corridors and also at the ends of the circulation spaces, guaranteeing the relationship of its teachers and students with the vegetation and the views to the outside.

The school group "Les Violettes" by the architecture studio HEMAA maximizes the surface area of ​​the playgrounds which is developed from two new buildings located on its western corner, in such a way that the new volumes and the existing primary school building are connected by two light openings that give rise to double-height spaces, favouring the union and taking advantage of the abundant natural light.

The building, from its materials such as wood and glass, reflects the foliage of the trees while its spatial arrangement emphasizes the transparency between the volumes that make up the project and the openness to the sky. Thus, in an evocative and poetic way, priority is given to raw materials that, in addition to stabilizing the structure and preserving its duration over time, adapt its appearance to the different seasons and the climate.

"Les Violettes" school group by HEMAA. Photograph by Sergio Grazia

"Les Violettes" school group by HEMAA. Photograph by Sergio Grazia.

Project description by HEMAA

The Les Violettes school complex is a village within the village of Mareil-Marly. Located on the heights of the town, the site is bordered by numerous remarkable trees and enjoys an unobstructed view to the west of the Paris metropolitan area, with the towers of La Défense visible in the distance. The existing buildings, with varied architectures from different periods, are nestled among trees and greenery, providing a privileged setting for children.

HEMAA designed a garden school that preserves and enhances the qualities of this natural environment. The building, with its material palette of wood and glass, reflects the foliage of the trees, while the spatial layout emphasizes transparency between building volumes and openness to the sky.

"Les Violettes" school group by HEMAA. Photograph by Sergio Grazia
"Les Violettes" school group by HEMAA. Photograph by Sergio Grazia.

To maximize the surface area available for playgrounds sheltered from prevailing winds, the two new buildings are situated in the western corner of the site. The two new volumes and the existing elementary school building are linked by two luminous gaps that accommodate the double-height through-halls : the first, at the junction with the existing structure, serves as the elementary school hall, while the second, combining the kindergarten hall and covered play area, brings abundant natural light to the interior street.

The kindergarten is entirely on the ground floor, with all classrooms offering direct access to the courtyard—an essential request from the teaching staff. In both the old and new courtyards, the open-ground areas around the existing trees have been enlarged. Rainwater is redirected into these slightly recessed areas to encourage natural infiltration.

"Les Violettes" school group by HEMAA. Photograph by Sergio Grazia
"Les Violettes" school group by HEMAA. Photograph by Sergio Grazia.

Evocative and Poetic Materiality
The choice of a lightweight, prefabricated French wooden structure reduced the noise and duration of the construction work, minimizing the impact on the site, which remained in use by the school community. The design highlights the fragmented nature of the structure with distinct treatments for the ground floor and the upper level.

The ground floor, a visual anchor for the children, forms a base that is widely open to the courtyards. It is clad in factory-treated vertical wooden slats. This cladding, made of French Douglas fir, is pre-aged with a gray finish to ensure its appearance remains stable over time. The upper level is wrapped in a reflective skin of mirrored aluminum panels interspersed with glass windows. The facade reflects the foliage of the trees, the sky, and the distant landscape, causing the building to change its appearance and colors with the seasons and weather. The softly curved and taut roofs appear to float above the courtyards.

"Les Violettes" school group by HEMAA. Photograph by Sergio Grazia.
"Les Violettes" school group by HEMAA. Photograph by Nicolas da Silva.

Inside, raw materials are prioritized. The wooden framework is exposed throughout, and the prefabricated concrete walls of the halls, which stabilize the structure, are left untreated. Acoustics are managed with compacted natural wood fiber placed betweenthe structural beams. The insulation is made of wood wool. The utility systems are exposed and neatly integrated.

The compact design of the building, which prioritizes playground space, led to the installation of central corridors that distribute rooms on both sides. To naturally illuminate these spaces, windows are incorporated into the walls separating classrooms and corridors. The ends of these circulation spaces are also glazed, ensuring that every point offers a view of the outdoors and surrounding greenery.

More information

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Architects
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Collaborators
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Hesters Oyon Architectes (competition phase), OTE - Engineering Office, OTELIO - Environmental Engineering Office.

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Client
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Municipality of Mareil-Marly.

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Area
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Gross Floor Area (SDP).- 1,997 sqm.
Usable Floor Area (SU).- 1,852 sqm.
Net Floor Area (SHON).- 2,074 sqm.
Outdoor Spaces.- 2,824 sqm.

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Dates
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2020 - 2024.

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Location
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Mareil-Marly (78), France. 

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Manufacturers
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Foundations - Structural Work - Site Installation.- BOUQUET SAS.
Wood Structure.- LCA LES CHARPENTIER DE L’ATLANTIQUE.
Waterproofing - Roofing.- SARMATES.
Facade Treatment.- DONABAT.
Exterior Joinery | Shutters.- J2M Entreprise.
Partitions - Linings | Suspended Ceilings.- KA CONSTRUCTIONS.
Interior Joinery - Fittings.- ATELIER DALBERGIA.
Metalwork.- REITHLER SAS.
Hard and Soft Flooring.- FLIPO SAS.
Painting - Signage.- LES PEINTURES PARISIENNES.
Plumbing - Sanitary.- CLIMAIRTEC.
Electrical Systems (High and Low Voltage) | HVAC - Smoke Extraction.- DERICHEBOURG ENERGIE.
Elevator.- TK ELEVATOR.
Roads and Utilities.- ALKEN SAS.
Fencing - Landscaping - Planting.- ESPACE DECO.

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Photography
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HEMAA Architectes is an architecture and urban planning studio founded in 2018 by Charles Hesters and Pierre Martin-Saint-Etienne. They undertake projects of all scales, encompassing public facilities, collective and individual housing, and cultural spaces, with an open and avant-garde approach.

Charles Hesters is an architect (HMONP) who graduated in 2012 from Paris Val de Seine and holds a Master's degree in Urban Planning from the University of Athens. He has worked at studios such as Brenac & Gonzalez & Associés, Gaëtan Le Penhuel, and Philippe Gazeau, and previously at Hesters-Oyon Architectes. After co-founding HEMAA in 2018 and participating in the Échelle Un incubator at EAV&T Paris-Est, he has been teaching at EAV&T Paris-Est and École des Ponts ParisTech since 2020, in the "matières à penser" department at the Master's level.

Pierre Martin-Saint-Etienne is an HMONP architect trained in Paris Val de Seine and holds a Master's degree in Urban Planning from UFRJ in Rio de Janeiro, in addition to specialized training in straw bale and earth construction. His professional experience includes stints at Brenac & Gonzalez & Associés, Philippe Gazeau, and Brunet Saunier, before co-founding HEMAA in 2018 and also participating in the Échelle Un incubator. Between 2018 and 2020, he was a teaching assistant at ENSA Paris-Malaquais within Studio PASS, teaching both Master 1 and the PFE program, and since 2020 he has been involved in the HMONP training program at ENSA Paris-La Villette.

Together, Hesters and Martin-Saint-Etienne develop a body of work that combines research, teaching, and built projects, guided by a shared conviction: to design architecture deeply conscious of its time and place, capable of engaging with nature and offering new, more respectful, understated, and sensitive ways of living.

Each project thus becomes an opportunity to question the scale and impact of buildings, adjust the dimensions of volumes, fragment masses, and dignify voids. The school complex they built in Normandy, for example, allowed them to work with local wood and slate, revisiting traditional forms. In Sartrouville, the school is built of solid load-bearing stone; in Evry, the Pôle Enfance is configured as a small village of pavilions constructed of rammed earth and wood in the heart of a park; and the house in Garches incorporates walls of reclaimed meulière stone from the demolition of the existing building. These investigations into site integration, the use of bio-sustained or reused materials, and the mobilization of local resources form the basis of their environmental approach. They eliminate all superfluous materials to return to an architecture composed of its essential elements and, through a passive design approach, strive for each project to achieve energy and carbon neutrality throughout its entire life cycle. They believe that nature and architecture are not opposites, but rather must find a suitable balance in each intervention so that, after their work, places and landscapes regain a new harmony.

HEMAA's trajectory has been accompanied by several exhibitions at leading institutions. In 2025, they participated in the Forum Bois International at the Grand Palais in Paris; in 2022, they presented their work at the Manifeste exhibition at La Plateforme Rennes of ENSA de Bretagne; and in 2019, they were finalists for the IP Factory project at the Pavillon de l’Arsenal as part of the Paris Rive Gauche exhibition. And in 2014 they exhibited at Futurs Immédiats, also at the Pavillon de l’Arsenal, with the Archipel de Seine project. Their work has also received outstanding recognition: in 2025 they won the Équerre d’Argent Première Œuvre for the Évry-Courcouronnes children's and sports center; in 2024 they were nominated for the European Union Prize for Contemporary Architecture —Mies van der Rohe Award— for the Heudebouville school complex; and in 2023 they were selected as Europe 40 Under 40 by The European Centre for Architecture Art Design and Urban Studies.

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Published on: January 23, 2025
Cite:
metalocus, MINERVA GARCÍA DE CASTRO
"A school in the trees. "Les Violettes" school group by HEMAA Architectes" METALOCUS. Accessed
<https://www.metalocus.es/en/news/school-trees-les-violettes-school-group-hemaa-architectes> ISSN 1139-6415
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