The two companies have also brokered a strategic alliance that will see them working together as Microsoft pushes Bing, its recently launched search engine to rival Google.
The addition of Razorfish to Publicis Groupe, which owns agencies including Saatchi & Saatchi, Leo Burnett and ZenithOptimedia, will see it generate 25% of its annual revenue from the digital sector.
This is up from the 21% it reported in the first half of the year.
The group already has a digital agency network called Digitas.
The Razorfish brand name will remain and become part of VivaKi, the new entity Publicis Groupe created in June last year.
Razorfish’s clients include Ford, Best Buy and McDonald’s. The agency will continue to work for Microsoft on digital strategy, creative and marketing services.
In a statement Publicis Groupe chairman and chief executive Maurice Levy says: “The acquisition of Razorfish is another step forward in realizing our strategic vision of building a world leader in digital communications, a critically important space for our clients.”