Lévy said it was a mistake to view the acquisition of Sapient as being purely about its digital offer to clients with no impact of the rest of the business.
"The whole portfolio of clients in Publicis PR operations will be affected," he said.
Lévy said his vision for the deal, announced yesterday, was for a "cross-pollination" of all the services offered by the group for clients of Publicis and Sapient.
He added: "Clients will have access to new tools and possibilities for communications. We are in the people business and broadening the base of collaboration opens up new horizons and opportunities."
He also spoke of a misconception that PR is an "old business" based purely on relationships.
"The reality is different," he said. "PR has been profoundly changed by the emergence of new means of communications such as social networks and bloggers. They give people the possibility of using their voice... even if it is just unnecessary noise, and this dramatically affects the job of PR agencies."
But Lévy said he was pleased that Publicis would achieve its target of 50 per cent revenues from its digital operation three years earlier than planned, in 2015.
"By the end of 2018 we should be at a much higher percentage and we might be able to give a prediction of that later in November," he said.
The chief executive also poured scorn on comments made by his WPP rival Sir Martin Sorrell yesterday, that the acquisition of Sapient was the behaviour of a "jilted lover" following the failed merger with Omnicom earlier this year.
"I don’t know what Martin knows about love. I don’t believe that’s his area of expertise. If it’s about hatred, it’s an area where he has a lot of talent. When it comes to love, he should leave it to the French."