The appointment, following a three-way pitch in July, is the precursor to a £3 million pre-Christmas TV campaign to build on the brand's number-four position in the UK boxed chocolate market.
Ferrero Rocher is famous for its history of spectacularly awful advertising epitomised by the "ambassador's party" ad. The work was dropped when Banks Hoggins was assigned the account in October 1999 but Ferrero has struggled to find a replacement.
The fraught relationship between Banks Hoggins and Ferrero came to a head in April when the agency said it had stopped working on the brand for which it devised the line "Give Ferrero Rocher ... grudgingly".
Ferrero claimed it had fired the shop because the advertising had performed below expectations. Research is said to have shown many viewers failed to understand the "double" ad in which a dinner party hostess fights her alter ego.
The Ferrero UK marketing director, Neil McIntosh, said the budget would make Ferrero the biggest pre-Christmas TV spender in its sector. Media buying will remain with Initiative Media.
"Ferrero enjoys a distinctive and unique positioning and the new campaign enhances its 'giving and sharing' appeal," he said.
Publicis conferred with its Nestle and United Biscuits clients before taking the Ferrero Rocher assignment. The agency is aligned with Nestle for drinks and petfood but not confectionery.
Grant Duncan, the Publicis joint chief executive, said: "Everybody may joke about the 'ambassador's party' but everybody remembers it. The trick is to convert that heritage into something exciting and plausible for the UK."