Montreal, Canada, 2026-02-04 -  blanchette archi.design unveils the Siège Social bistro and Café Social, an interior design project located on the ground floor of 1111 Saint-Charles Street West in Longueuil. Commissioned by Groupe Mercille, and carried out by PR Desjardins, this new hybrid space extends and transforms the experience of the office tower's existing lobby, toughtfully reinterpreting the architectural and aesthetic codes of corporate environments from the 1960s and 1970s.

Conceived as a natural extension of the postmodern lobby, the project revisits the formal strictness and rationality characteristic of that era, translating them into a contemporary, warm, and welcoming experience. A cross between a café, a bistro, and a social space, the venue is anchored in its tertiary context, while offering a new culture of uses within the workplace.

Spanning an area of approximately 2,300 square feet, the layout is organized around two distinct and complementary worlds. The Café Social, located in continuity with the common corridor, acts as a lively and accessible transitional space, bustling with activity throughout the day. The Siège Social bistro, designed as an informal ‘head office’ for the neighbourhood, opens generously onto the terrace and forecourt, encouraging meals, meetings, and gatherings.

A strong material theme ensures the project's coherence: square white ceramic tiles with a matte finish, used on both vertical surfaces and built-in furniture. Inspired by the patterns in the existing lobby, this materiality becomes an identifying and structuring motif. A walnut wall punctuated with glass openings filters the light between the café and the bistro, creating a diaphanous separation that maintains a constant visual dialogue between the spaces.

"Above all, the project sought to transform highly codified office references into an attentive and human experience, where design supports uses without ever constraining them," says Sarah Arsenault, interior design project manager at blanchette archi.design. "The pattern, materials, and light were worked on as tools of continuity and comfort, in order to create a place that is both familiar and distinctive."

The atmospheres are distinguished by precise work on materials and colours. The café features travertine, mustard tones, and dark wood finishes, while the bistro adopts an enveloping palette of terracotta, deep greens, light wood, and integrated vegetation. Inspired by the modernist interiors of the 1960s and 1970s, the colour palette has been reinterpreted in a contemporary, understated, and timeless style.

Lighting plays a central role in the identity of the space, allowing the atmosphere to evolve from morning to evening thanks to a dim-to-warm system integrated into the bistro's ceiling. Inspired by the vertical blinds found in office environments, this suspended ceiling introduces movement, rhythm, and depth, transforming a functional reference into an attentive spatial experience.

For Groupe Mercille, this project is part of a clear desire to contribute to the revitalization of a neighbourhood undergoing transformation, beyond the office tower itself. Designed as a new destination open to the outside world, the Bistro Siège Social contributes to the dynamism of this redevelopment hub, engaging with users in the area and the neighbouring university community.

"The Bistro Siège Social is not just a convenience integrated into a building: it is an accessible, unifying place with its own identity, which contributes as much to the quality of life at work as it does to the vitality of the neighbourhood," says Hélène Mercille, President of Groupe Mercille. "Design played a key role in creating a distinctive and sustainable space, capable of supporting new uses and the effervescence of the environment."

Through a skillful reinterpretation of office codes, the Siège Social bistro and Café Social offer a hybrid, contemporary, and welcoming space, where architecture and interior design play a key role in creating a new sense of sociability at the heart of the workplace.