Kemoun and Rebbouh plan to open "five or six" offices in key European markets in total. Their operation will launch in Paris in September with WPP providing KR with support in systems, research and media buying. The network will offer planning and buying across traditional and digital media.
But Kemoun and Rebbouh stressed that KR would not form the European arm of Maxus, WPP's third media network. Access to WPP's Kantar Group research arm is a key part of the deal.
The pair, nicknamed "the twins" because they have worked in tandem for more than 20 years, aim to build their European network through acquisitions.
Growing a presence in the French market is their first priority.
Kemoun and Rebbouh, who quit their posts as the chief executives of Aegis Media Europe last November, agreed to a non-solicit clause that will prevent them talking to Carat clients until this November.
They said KR Media's objective is to handle planning and buying on big accounts. On the acquisition strategy they said that they will be opening offices "encompassing planning and buying and all 100 per cent under our control".
Sir Martin Sorrell, the WPP group chief executive, said: "We are very excited by the prospect of supporting Bruno and Eryck in their new venture and investing in it. We are certain that given their successful careers and reputations, KR Media will be an extremely attractive opportunity for clients and talented people in our industry."
Kemoun and Rebbouh, credited with building Aegis Media into a powerhouse in France and then across Europe, left after disagreements with the Aegis chief executive, Doug Flynn.