He was hired by Eric Zadjemann, the chief executive of both agencies, who is in the process of bringing the two businesses together in a joint venture.
Behaegal will be running the businesses' creative departments, as well as working on global campaigns for Lowe's worldwide network.
Behaegal began his career as an art director at Ouvriers du Paradis/United. He then held creative posts at RSCG, FCB, CLM BBDO and Steak/Red Cell.
He said: "This is an exceptional opportunity."