blanchette archi.design presents Siège Social bistro and Café Social, a new hybrid hospitality space on the ground floor of 1111 Saint-Charles Street West in Longueuil, Quebec. Commissioned by Groupe Mercille and delivered by PR Desjardins, the project reworks the existing office lobby into a spot that serves both the building and the wider neighbourhood.
Drawing from the architectural language of corporate interiors from the 1960s and 1970s, the design revisits an era defined by order and clarity, translating those references into something decidedly contemporary and approachable. Conceived as a continuation of the postmodern lobby above, the space blurs the line between workplace amenity and public venue, offering a café, a bistro, and a social setting under one roof.
At just over 2,300 square feet, the plan is organised around two complementary atmospheres. Café Social sits alongside the main circulation route, operating as an energetic point of passage from morning through to late afternoon. Beyond, the Siège Social bistro opens onto a terrace and forecourt, imagined as an informal head office for the area, encouraging lunches, meetings, and anything in-between.
Material continuity plays a central role throughout. Matte white square ceramic tiles wrap walls and joinery, referencing patterns found in the original lobby and giving the project a clear visual identity. A walnut partition with glazed openings filters light between café and bistro, maintaining sightlines.
“Above all,” says Sarah Arsenault, interior design project manager at blanchette archi.design, “the project sought to transform highly codified office references into an attentive and human experience, where design supports uses without ever constraining them.”
The two spaces are distinguished through colour and finish. Travertine, mustard tones, and dark wood define the café, while the bistro shifts towards terracotta, deep greens, light timber, and integrated planting. Lighting evolves throughout the day via a dim-to-warm system, with a suspended ceiling inspired by office blinds.
The food offering follows the same clear, unfussy logic. Lunchtime brings well-seasoned tartares, croque-monsieur, and homemade fries, paired with low-alcohol cocktails designed for a productive afternoon. Open to the public and the neighbouring university community, Siège Social positions itself as a new gathering point for an evolving district.
@lesiege.social
@blanchettearchidesign
Bistro Siège Social Longueuil Photography, Alex Lesage via v2com.
