It addition to BETC’s 900 colleagues, Les Magasins généraux’s 20,000-square metres of space will provide workspace for partners and other creative businesses to work on projects.
Re´mi Babinet, founder and chairman at BETC, said: "Successful contemporary business happens where culture meets industry and entrepreneurism. Our ambition is for Les Magasins généraux to facilitate connection between varied industries to enable experimentation and serendipitous collaborations to develop and grow."
Les Magasins généraux opened as a flour and grain warehouse in 1931 and operated until 2000 when it closed its doors. Left derelict, the site was popular with street artists and began to be known as the "graffiti cathedral of Paris".
The offices have been designed in a way that Babinet hopes will foster innovative creative collaboration. An area called The Garage offers dedicated production facilities for film, music, design, radio and digital.
Babinet said: "We don't stop living when we go to work. Cities are living and connected. City-dwellers experience emotion, energy, freedom and the unexpected. It’s important that they make spaces their own.
"Les Magasins généraux’s structure allows its creative inhabitants to do the same – live with the freedom to create."
The area of Pantin already lays claim to the production and development departments of Hermès, Chanel and Gucci as well as arts organisations such as Philharmonie de Paris, Thaddaeus Ropac art gallery and the Centre National de la Danse. The New York Times has called the area "the Brooklyn of Paris".
Babinet founded BETC as the Havas-backed shop Babinet Tong Cuong with Eric Tong Cuong in 1994. Mercedes Erra joined them in 1995 and the trio renamed the agency BETC. It works with brands including Canal+, Air France, Peugeot and Lacoste.
The design of the building was developed by Babinet, BETC art director Aurélie Scalabre, design company T&P Work UNit, which had created BETC’s original office, and 12 separate teams of designers and architects.
The architect Frédéric Jung led the renovation, which has retained the building’s 1.4km of hallways, and created outdoor spaces including a green garden on the roof.
The ground floor of Les Magasins généraux is a public space, and neighbours or visitors are welcome at the event space La Grande Salle, organic food hall Le Pantin and Les Docks de la Bellevilloise, a live music venue and restaurant.
From January next year BETC will put on its own cultural events, offering an international programme of art, music, food and drink, tech, dance, innovation and culture.