Vivendi is buying the 60 percent stake Bollore Group owns in Havas, the French advertising/PR combine, for $2.5B.

Arnaud de Puyfontaine, CEO of Vivendi—owner of Universal Music Group and Canal Plus Group (pay TV)—said the deal represents a major milestone in Vivendi's drive to become global leader in content, media and communication.

"Havas brings its expertise in consumer science, data analytics and new creative formats to the entire Vivendi group," he said in a statement.

Vivendi said its offer represents a "reasonable premium" based on Havas' operational performance compared to its peer group. It also noted that management of Havas said the global advertising market in 2017 is marked by "uncertainties in organic growth and profitability."

Yannick Bollore, CEO of Havas Group, said joining forces with Vivendi will provide it with "new strategic and financial resources."

The Vivendi/Havas tie-up is subject to approval by France's government.