Dumont has been based in Asia for 20 years, and most recently worked as a consultant for the past seven years, having left the PR agency Edelman in 1998.
He will report to Michael Birkin, chairman and CEO of Omnicom Asia Pacific, and has been tasked with heading Omnicom's expansion in Asia, initially focusing on Greater China.
The major ad holding companies, along with most of the Western business world, are looking to China as one of the key growth markets, but negotiating the commercial landscape is not always an easy task.
Dumont's involvement in China has seen him retained as an adviser by bodies such as the World Health Organisation and the French government. He takes up his role immediately and will be based in Beijing.
Birkin said: "Serge has a brilliant reputation, a proven track record and extensive experience in Asia. We see his appointment as a critical step in driving many of our strategic initiatives."
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