The move is being seen as grip-tightening by the French group over its subsidiary.
The appointment comes as Hytner, the former chief executive of Publicis' London agency, completes a year's sabbatical on the London Business School's Sloan Masters MSc programme, having earlier stepped down from his role at the agency.
Hytner had been expected to take a broader role within Publicis ever since enrolling on the Sloan course, which is intended to equip managers in their 30s and 40s for the most senior positions in business and industry.
A Cambridge law graduate, Hytner joined Publicis in 1997, having run the Henley Centre and been the chief executive of Ammirati Puris Lintas. His period at Publicis coincided with the agency evolving into one of the most significant players in its network and its rise to become the UK's third-ranking shop.
Three years ago, Hytner was mooted as a candidate for chief executive of the ITV Network.
Hytner fills the role long occupied by Derek Bowden, who quit as the European chairman in 2001 and was later appointed as the chief executive of Ipswich Town Football Club.
Hytner's is the second recent high-profile change to senior management within the Publicis Groupe. The French network poached Saatchis London's creative director, Dave Droga, putting him into the position of Publicis' global creative director.
Neither Hytner nor Kevin Roberts, the worldwide chief executive of Saatchis, were available for comment.