"The Publicis Worldwide brand is not clearly defined because it gets mixed up with Publicis Groupe," Mr. Sadoun said. "At Cannes, we have moved up from 17th most creative agency three years ago to number seven. We hope we will soon move into the top five. We get 40% of U.K. revenues from digital, and 35% globally. What's missing is collective direction."
By the time Mr. Wieynk assumes the new job, however, the proposed merger may have finally been completed, making Publicis Worldwide a unit of a mega-sized agency holding company called Publicis Omnicom Group. Mr. Wieynk left his post as international VP at AKQA in January, but can't take up the new role at Publicis Worldwide until the end of this year because of contract issues with AKQA owner -- and Publicis Groupe rival -- WPP.
"I'm very respectful of the Publicis name, and we need to give it a clear identity as an agency of the future, not a legacy agency," Mr. Wieynk said.
He takes over the U.K. role from Nigel Jones, who said in September that he was leaving to take a global strategy role at DraftFCB. The Nordic countries are an added responsibility.
Mr. Sadoun said Mr. Wieynk will play an important role in the transformation of the network, using what he learned during 16 years as part of a team building AKQA globally. "Being digital locally is simple," he said. "You put a bunch of guys in an office, they do a digital campaign. The difficulty is digital at scale, which is where Guy's global experience is absolutely key for us because our clients are global."
Mr. Wieynk said AKQA's experience was illustrative. "If AKQA hadn't changed its business or evolved itself it would have been a U.K.-based web development agency," he said. "What we really did well is we managed to scale our business, and I'm interested in using that experience working with Arthur."
Another point of differentiation for Publicis Worldwide is that it's a European, non Anglo-Saxon network, according to Mr. Sadoun. "It's another philosophy, another culture," he said. "We are closer to everywhere. It makes our view of the world that much more global."
Asked about the effect of the planned, if belated, combination between Publicis Groupe and Omnicom Group, Mr. Sadoun said business was proceeding as normal. "There is no impact for us today," he said. "We all of us have a lot of other things on our plates at the moment."
Mr. Sadoun, who spent half his career at Omnicom agencies -- including a stint as CEO of TBWA Paris -- looks well-placed to come out with a strong role in a merged entity. But he dismissed such speculation as "science fiction."
"When you are a Frenchman there is no better job than running Publicis Worldwide," he said.
Mr. Wieynk said the uncertainty surrounding the proposed merger was not important. "Ultimately you've got two very large businesses that are both fine whatever happens," he said. "I don't think it will affect me in the short term."
When he eventually joins Publicis Worldwide, Mr. Wieynk will oversee Publicis London, Poke, Publicis Chemistry and Publicis Blueprint, as well as Skaandali Publicis in Finland, Kitchen in Norway, and Reputation in Denmark, working with clients including Procter & Gamble, Renault, L'Oreal, Citi Group, the Coca-Cola Company and Samsung. He will report directly to Mr. Sadoun and will be a member of the Publicis Worldwide global management board.
Dylan Williams, former chief strategy officer and a partner at Mother, will also join Publicis Worldwide later this year as chief strategic and innovation officer, based in London. In October, Mr. Sadoun promoted Loris Nold, whom he described as his second-in-command, to CEO Asia-Pacific and Africa.