Arthur Sadoun was in full sales mode as Publicis Groupe finalized its $3.95 billion Epsilon acquisition this week.

According to the holding group CEO, the addition of that data-driven marketing firm will provide his company with an advantage over not only direct rivals like WPP and IPG but also the consulting firms encroaching on its turf.

The key differentiator, as Sadoun has said repeatedly in a series of interviews since news of his company’s interest in Epsilon initially broke, is first-party data, or information that marketers collect about their own customers. He sees this information as far more valuable than second- and third-party data, which is often aggregated by outside companies and then resold to advertisers and agencies.

"What I heard most from clients in Cannes is [that] it’s time to take back control of our customers." Arthur Sadoun, CEO, Publicis Groupe

“We’re not here to tell you we have the best data,” Sadoun told Adweek. But he argued that the combination of behavioral information coming directly from clients’ and the “vision” provided by Epsilon—which will sit in the center of the Publicis organization—gives every company within his network an advantage.

“In Cannes, we could feel the pressure coming from the ecommerce platforms … and the rise of the DTC brands,” he continued. “What I heard most from clients in Cannes is [that] it’s time to take back control of our customers.”

And how will Publicis help them do that? By placing Epsilon at the center of its agency network, according to Sadoun.

As this week’s announcement put it, “Every Publicis Groupe client will be able to access Epsilon through their Groupe Client Leaders,” effective immediately in the U.S.

Sadoun also shot down any rumors of streamlining or rebranding the Epsilon organization, stating that this is “the last thing you want to do when you buy a company like that” and adding, “It’s a brand with a lot of awareness, and even more since we made the acquisition.” Instead, he said Publicis’ PeopleCloud platform would be folded into the newly acquired entity.

Echoing predecessor Maurice Levy’s famous “No silo, no solo, no bozo” mantra, Sadoun added that he aimed to make Epsilon a silo-free organization. For example, he said a client of Publicis agency Leo Burnett would be able to “seamlessly” access both Epsilon and Sapient for data and business transformation services beyond traditional creative advertising.

He went so far as to claim that Sapient can beat “Accenture in particular” at the transformation game due to its “customer-first approach.”

“This is something we’ve been doing on a smaller scale that we can now do on a larger scale,” Sadoun said.

As for proving whether his confidence is justified, client responses over the next 12 months are crucial. Citing reports that put Publicis atop the new business list for 2018, he said, “The big question for us now is execution.”