Marshall takes control of the agency after five years as the managing director. He replaces Dennis Kerslake, who has been made the regional director of the Publicis network's HP business in Europe, the Middle East and Africa.
The changes come as Publicis seeks to strengthen its hold on the HP business - one of the network's flagship integrated accounts. In Europe, which is its second-biggest market behind the US, it is worth an estimated $250 million.
In July, Publicis won HP's UK online ad business from WPP's Banner and parts of its direct marketing from Omnicom's Tequila\London, without a pitch.
However, in the US, Publicis & Hal Riney shares the global creative account with Goody Silverstein & Partners.