The practice will be headed up by Ali Nehme, who will report into Digitas global brand president Michael Kahn.
Nehme is taking on the position of commerce global practice lead at Publicis Media after previously holding the role of president of commerce and innovation at Publicis Media EMEA, where he worked on accounts including L’Oréal, Nestlé, Procter & Gamble and Samsung.
The new practice follows on from Publicis Media boss Steve King forming seven practices during a major reorganisation that involved the retiring of the the Starcom Mediavest Group and ZenithOptimedia brands and the formation of a four media networks to create a "flatter organisational structure".
The other six practices are: data, technology and innovation; content; trading and buying; performance; business development and communications; business transformation; and analytics, research and insight.
The commerce practice will have three areas of focus. The first is "strategy and acceleration", which will seek to help clients grow their business through their direct-to-consumer sites and through ecommerce websites.
A second area of focus for the practice is "media and investment" that will involve "planning and linking media to commerce" and recommending areas of investment.
"Content and merchandising" is the third focus area, in which the unit will seek to help brands to increase the visibility of their products and improve the overall customer experience.
Nehme will head up a dedicated team of regional commerce leads in the Americas, EMEA and APAC regions, while also overseeing commerce specialists within the individual networks.
King said: "Commerce is a massive growth opportunity for our business and the industry-at-large. Ali’s deep expertise and experience guiding commerce strategy and capabilities for key agencies and their clients will help us effectively lead and manage the intersection of media and commerce to maximise brand sales online and across marketplaces."