“We are concerned about the situation in Europe,” he told CNBC. “If you look at the macroeconomics, they are expecting GDP (gross domestic product) growth of 1.6 per cent – which is rather low.”

“Germany is doing well. The U.K., from a macro standpoint is doing extremely well. Less so in our own situation and we are improving our position.”

Last July, Publicis cut its 2015 sales forecast, warning that tougher conditions in the U.K. and Latin America could hurt an improvement that had been seen in the first half of the year.

It also reduced its full-year agencies market growth forecast to 2.5 percent from 3 percent and said its own sales would remain “in line” with the trimmed outlook.