Leibar Seigneurin Architectes

What Leibar Seigneurin Architectes does

Leibar Seigneurin Architectes is a private French architecture firm founded in 1991 by Xavier Leibar and Jean-Marie Seigneurin, headquartered in Bayonne (Pays Basque) with a secondary office in Bordeaux. Operating as a SARL with approximately 20 collaborators (16 architects, 3 engineers, and 1 administrative staff), the firm delivers full-service architectural missions (mission complète base loi MOP) across six practice areas: residential housing (Logements), culture and heritage (Culture et Patrimoine), workplaces (Lieux de Travail), production and environment (Production et Environnement), public spaces (Espace Public), and education (Enseignement). It holds ISO 9001 certification and has completed more than 150 projects delivering over 5,000 housing units since inception.

The firm generates revenue through per-project commissions from two principal client bases: French public-sector entities (municipalities, departmental and metropolitan councils, social housing operators) and private developers (including ICADE, Cogedim, Eiffage, Bouygues Immobilier, Nexity, Kaufman & Broad, Sogeprom, BPD Marignan, and Fayat). Pricing follows French architectural conventions, tied to construction cost (Montant des travaux), surface area (m²), and mission scope, with disclosed project fees ranging from roughly €0.78 M to multi-million euro commissions on buildings with construction values up to €44 M. GTM is sales-led, with work sourced through architectural competitions, public tenders under loi MOP, and direct developer commissions.

The practice emphasizes a defined architectural philosophy of permanence, balance, and stability — drawing on Basque vernacular traditions and references to sculptors Jorge Oteiza and Eduardo Chillida — and combines this with technical execution capabilities including BIM Level 2 on select projects, certifications across HQE, RT 2012, BBC, THPE, NF Habitat, and Effinergie standards, and notable projects such as the Steven Holl-collaborated Cité de l'Océan et du Surf in Biarritz. In 2021, four new associates were elevated to broaden the leadership team, and the firm has expanded geographically from its Basque Country roots to projects across Nouvelle-Aquitaine, Occitanie, Pays de la Loire, Île-de-France, PACA, and Grand Est.

Name

Leibar Seigneurin Architectes

Legal name

SARL Leibar Seigneurin

Website

https://leibarseigneurin.com

Company type

Private

Founded year

1991

Operating status

Operating

Headcount range

11–50 employees

Short description

Leibar Seigneurin Architectes is a French architecture firm founded in 1991, headquartered in Bayonne with a secondary Bordeaux office, delivering full-service architectural design across housing, education, culture, workplaces, public space, and production/industrial projects for French municipalities, housing authorities, and private developers.

Ownership category

akta.pro rank

Product category

Architectural Services

NAICS

Architectural Services (54131), Landscape Architectural Services (541320)

akta.pro primary industry

Architectural Design Services (BPAHAKAA)

akta.pro secondary industries

Landscape Architecture & Site Design (BPAHAKAC), Architectural Reconfiguration & Structural Alterations (HSAPAEAB)

Keywords

• Architectural design services
• Residential housing design
• Public infrastructure architecture
• Cultural heritage restoration
• Urban planning services

Headquarters

HQ city

Bayonne

HQ country

France

HQ region

Europe

Offices2 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Technology or R&D, Marketing or Sales, Infrastructure

Revenue model

1. Architectural services — public sector: The firm generates revenue through architecture and engineering design commissions from public sector clients including municipalities, departmental councils, metropolitan authorities, and housing organizations, billed on a per-project basis for full-service architectural missions (Mission complète base loi MOP).

Pricing tiers

Go-to-market motion1 record

Distribution channels2 records

Marketing channels3 records

Core offering

Leibar Seigneurin Architectes is a full-service French architecture firm providing design, engineering coordination and project management under the mission complète loi MOP framework. The firm delivers housing, cultural, educational, workplace, public space, industrial and urban planning projects for public sector clients (municipalities, departmental councils, metropolitan authorities, social housing organisations) and private developers across France.

Product overview

Leibar Seigneurin Architectes is an architecture firm offering comprehensive architectural services across six main practice areas: residential housing (Logements), culture and heritage (Culture et Patrimoine), workplaces (Lieux de Travail), production and environmental facilities (Production et Environnement), public spaces (Espace Public), and education (Enseignement). Founded in 1991 and based in Bayonne and Bordeaux, France, the firm provides complete architectural services from design through construction supervision for public and private clients throughout France.

Differentiator

Problem solved

Functional benefit

Products and services

• Logements (Residential Housing) Architectural design services for residential housing projects including collective housing, social housing, individual houses, and mixed-use developments with commercial spaces, serving housing authorities, social landlords and private residential developers across France.
• Culture et Patrimoine (Culture and Heritage) Architectural design services for cultural facilities, heritage restoration and monument projects including museums, cultural centres, and rehabilitation of historic buildings, serving public sector cultural authorities and heritage institutions.
• Lieux de Travail (Workplaces) Architectural design services for office buildings, business centres, administrative buildings and commercial workspace design, serving corporate occupiers, public administrations and developers commissioning workplace real estate.
• Production et Environnement (Production and Environment) Architectural design services for industrial facilities, food processing plants, water treatment facilities, and production environments, serving industrial operators and manufacturers in France.
• Espace Public (Public Spaces) Architectural and landscape design services for urban development, public squares, waterfront improvements and public space projects, serving municipalities, metropolitan authorities and developers of urban regeneration programmes.
• Enseignement (Education) Architectural design services for educational facilities including schools, colleges, universities and training centres, serving municipalities, departmental councils and educational institutions commissioning new builds and extensions.

Quantifiable outcome

• 150+ completed architectural projects
• +2 more outcomes

Named customers30 records

Segments2 records

Ideal customer profiles2 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature3 records

Partnerships

Five partnerships are on record, tiered flagship, core, minor and major.

• Steven Holl ArchitectsflagshipStrategic or Co-development Partner · 1 January 2021Joint venture on the Cité de l'Océan et du Surf project in Biarritz (4,480 m² SU, 21 M€ HT), where Steven Holl acted as lead architect and Leibar & Seigneurin as associated architects under a PPP framework. This collaboration brought international architectural recognition to the firm.
• Julien Baronnet, Clémence Laur, Clément Latieule, Jules Mousseigne (Associés)coreOthers · 1 January 2021Four associates were elevated to partner status in 2021 to continue delivering ambitious projects and address future challenges. The firm has a co-founding partnership of Xavier Leibar and Jean-Marie Seigneurin.
• D—AD—A (Studio DADA)minorImplementation/ SI/ Consulting Partner · 1 January 2021Listed as a contributor to the website/legal mentions, suggesting a web design/creative partnership.
• Atelier 909minorImplementation/ SI/ Consulting Partner · 1 January 2021Listed as a contributor to the website/legal mentions, suggesting a design/creative partnership.
• NexitymajorStrategic or Co-development Partner · 1 January 2021Coordinated an urban block of 182 housing units at Les Quais de Pantin (93), with Leibar & Seigneurin as lead architect and coordinator of a team including SOA architects and Antonini Darmon. 97 of 182 units designed by the firm (12,427 m², 17.9 M€ HT).

Scale indicators5 records

Recent moves6 records

Expansion highlights5 records

Direct peers

• Bruno Gaudin Architectes: French architecture firm with comparable heritage/restoration and cultural-facility practice including Louvre-Lens-related projects; similar scale and public-commission profile to Leibar Seigneurin.
• Atelier Architectes (group): French groupement of architectural practices sharing operations similar to Leibar Seigneurin's collective model; relevant comparable for a SARL-structured French architecture firm competing in public procurement.
• ECDM Architectes: French mid-sized architecture firm based in Paris with comparable portfolio of housing, public facilities and large-scale urban projects; closest functional peer to Leibar Seigneurin's mixed public-and-private French practice.
• SOA Architectes: Parisian architecture firm coordinated with Leibar Seigneurin on the Les Quais de Pantin urban block; comparable as a French boutique practice working with major developers on residential programmes.
• Antonini Darmon: French architecture firm collaborating with Leibar Seigneurin as co-architects on Nexity's 'Les Quais de Pantin'; directly comparable in scope of residential and urban regeneration projects in France.
• Hamonic+Masson & Associés: Paris- and Bordeaux-based architecture practice of similar scale focused on housing, mixed-use developments, and public facilities; directly comparable to Leibar Seigneurin's residential and mixed-use expertise.
• TVK (group): French architecture and urbanism practice of similar scale focused on metropolitan strategy, housing, and public space design; closely comparable on 'Espace Public' typology.

Broad incumbents

• Architecture-Studio: Larger, established international French architecture practice with much broader portfolio (cultural, public, urban, commercial) and offices worldwide; competes for the same French public tenders and developer commissions at greater scale.
• Wilmotte & Associés: Larger French architecture and design group covering residential, cultural, workplace, and public sectors with international offices; competes for the same premium and public commissions as Leibar Seigneurin.
• Jean-Paul Viguier et Associés: Larger French architecture firm with broad portfolio of offices, residential, and public buildings; competes for major French developer commissions alongside Leibar Seigneurin.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks7 records

Key highlights7 records

Customer concentration

• Xx.com/lsarchitectes
• LinkedInlinkedin.com/company/agence-leibarseigneurin
• Instagraminstagram.com/leibarseigneurin
• Pinterestpinterest.fr/lsarchitectes
• Facebookfacebook.com/leibarseigneurin

Compliance1 record

Revenue estimate

Valuation estimate

Number of profiles

Profiles6 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Leibar Seigneurin Architectes