In an interview with The New York Times this month, Publicis’s longtime chief, Maurice Lévy, said he expected much of the growth in the advertising sector to come from emerging markets and mobile and digital advertising. Publicis has been making aggressive acquisitions in digital advertising including agencies like Rosetta and Razorfish.

“I think we are all talking a lot about what the future markets of mobile will be and how we will be able to get the revenue we are expecting from this market,” Mr. Lévy said, citing a $15 million investment in a mobile polling start-up that is focused on emerging markets like Africa. “It is a huge market with incredible possibility for the future. Everyone is fighting very hard and trying to find solutions to get these next billion consumers,” he said.

Omnicom, which analysts say has focused more on expanding its digital operations organically as opposed to through acquisitions, stands to benefit from the media buying power of the Starcom MediaVest Group, a division of Publicis that is one of the largest media agencies in the world. In April, Starcom signed a multiyear deal with Twitter to combine some of the resources that they both use for measuring and tracking data and advertising. That deal was estimated to be hundreds of millions of dollars.

Last year, revenue at Publicis increased nearly 14 percent to $8.8 billion, while revenue at Omnicom increased 2.5 percent to $14.2 billion.