They have been earmarked to head and take equity in a newly created media network after Sir Martin Sorrell, the WPP group chief executive, confirmed last week that the holding company is to launch a third network to complement its existing MindShare and Mediaedge:cia networks.
Rebbouh and Kemoun have been pursued by rival networks since they left Aegis last November. They are credited with driving the success of Carat International and with building top-level relationships with clients that were envied by rival agencies.
The pair, who have worked in tandem since 1985 when they founded a media agency called 2010 Medias with Carat France, are expected to be based in Paris, where they will be responsible for building a network that will help WPP manage potential conflict.
Sources said that Rebbouh and Kemoun would be a good fit for WPP's as-yet unnamed media operation.
WPP's Mediaedge:cia and MindShare agencies are relatively small in the French market, which allows them space to build a large domestic French operation as well as a new network.
Rebbouh and Kemoun were close to clients including Renault and the supermarket chain Carrefour while they were at Aegis.
After selling their agency to Aegis in 1991, they joined the board a year later and became the joint chairmen of Carat France in 1995. In their Aegis role, running Carat and its sister agencies across Europe, Rebbouh and Kemoun oversaw 43 offices in 26 countries.
The pair departed from Aegis following disagreements with its chief executive, Doug Flynn, over strategy.
Since leaving Aegis, the duo have launched their own company, KR Media, which has invested in the publishing subscription company Press Informatique.