Euro RSCG said it will handle the development of the brand on its core business, as well as "the creation of a range of derivative products" in Europe, the US and Asia.
Atari's recent game releases include 'The Witcher' on the PC, 'Dungeons & Dragons Tactics' on the PSP and 'Tamagotchi Party On!' on the Nintendo Wii.
Last year, DraftFCB London won the global advertising account for Atari following a two-way pitch against Euro RSCG 4D. It is unclear whether Euro RSCG has taken this work from DraftFCB.
Draft FCB was initially tasked with redeveloping Atari's website. The brief also included brand advertising and strategy, direct marketing and online.
French videogames group Infogrames bought the Atari name in 2001 when it acquired the interactive entertainment business of toy business Hasbro for $100m.
Atari led the home-console market in the late 70s and early 80s with games including 'Pong', 'Space Invaders' and 'Asteroids', along with its Computer Video System, later rebranded the 2600.
It was owned by Warner, which sold it on in the 90s to Hasbro.