Publicis Chief executive Levy and Omnicom Group head Wren react during a joint news conference in Paris
Maurice Levy (L) , French advertising group Publicis Chief executive, and John Wren, head of Omnicom Group react during a joint news conference in Paris, July 28, 2013. Publicis and Omnicom have announced merger plans to create the world's biggest advertising group, worth $35.1 billion, a tie-up that could put pressure on rivals to do deals to keep pace. REUTERS/Christian Hartmann (FRANCE - Tags: BUSINESS MEDIA)
Publicis Chief executive Levy and Omnicom Group head Wren react during a joint news conference in Paris
Maurice Levy (L) , French advertising group Publicis Chief executive, and John Wren, head of Omnicom Group react during a joint news conference in Paris, July 28, 2013. Publicis and Omnicom have announced merger plans to create the world's biggest advertising group, worth $35.1 billion, a tie-up that could put pressure on rivals to do deals to keep pace. REUTERS/Christian Hartmann (FRANCE - Tags: BUSINESS MEDIA)
Publicis Chief executive Levy and Omnicom Group head Wren react during a joint news conference in Paris
Maurice Levy (L) , French advertising group Publicis Chief executive, and John Wren, head of Omnicom Group react during a joint news conference in Paris, July 28, 2013. Publicis and Omnicom have announced merger plans to create the world's biggest advertising group, worth $35.1 billion, a tie-up that could put pressure on rivals to do deals to keep pace. REUTERS/Christian Hartmann (FRANCE - Tags: BUSINESS MEDIA)
Publicis Chief executive Levy and Omnicom Group head Wren react during a joint news conference in Paris
Maurice Levy (L) , French advertising group Publicis Chief executive, and John Wren, head of Omnicom Group react during a joint news conference in Paris, July 28, 2013. Publicis and Omnicom have announced merger plans to create the world's biggest advertising group, worth $35.1 billion, a tie-up that could put pressure on rivals to do deals to keep pace. REUTERS/Christian Hartmann (FRANCE - Tags: BUSINESS MEDIA)
Publicis Chief executive Levy and Omnicom Group head Wren react after the signature of merger documents during a joint news conference in Paris
Maurice Levy (L) , French advertising group Publicis Chief executive, and John Wren, head of Omnicom Group react after the signature of merger documents during a joint news conference in Paris, July 28, 2013. Publicis and Omnicom have announced merger plans to create the world's biggest advertising group, worth $35.1 billion, a tie-up that could put pressure on rivals to do deals to keep pace. REUTERS/Christian Hartmann (FRANCE - Tags: BUSINESS MEDIA)
Publicis Chief executive Levy and Omnicom Group head Wren pose during a joint news conference in Paris
Maurice Levy (L) , French advertising group Publicis Chief executive, and John Wren, head of Omnicom Group pose during a joint news conference in Paris, July 28, 2013. Publicis and Omnicom have announced merger plans to create the world's biggest advertising group, worth $35.1 billion, a tie-up that could put pressure on rivals to do deals to keep pace. REUTERS/Christian Hartmann (FRANCE - Tags: BUSINESS MEDIA)
Publicis Chief executive Levy and Omnicom Group head Wren pose during a joint news conference in Paris
Maurice Levy (L) , French advertising group Publicis Chief executive, and John Wren, head of Omnicom Group pose during a joint news conference in Paris, July 28, 2013. Publicis and Omnicom have announced merger plans to create the world's biggest advertising group, worth $35.1 billion, a tie-up that could put pressure on rivals to do deals to keep pace. REUTERS/Christian Hartmann (FRANCE - Tags: BUSINESS MEDIA)