The WPP agency, which has held the UK account since 1999, was unseated along with fellow Group M agency MEC, in a group-level pitch process that kicked off in May.
Publicis Groupe pitched against the incumbents Group M and Omnicom Media Group. It will now create a stand-alone team with a new name to manage the business.
Mercedes spent £13.8 million on UK media in the year to September 2012.
Maxus picked up Mercedes’ UK media account in 1999 when it was known as BJK&E, before it was bought and rebranded by WPP. MEC was the incumbent on Mercedes in some European markets outside the UK, as was OMD.
The review was run through Mercedes’s headquarters in Stuttgart, Germany. Daimler confirmed that 14 European markets were "actively involved" in the pitch.
Publicis’s UK agencies include ZenithOptimedia, which handles media for Toyota and Lexus in the UK.
A Publicis Groupe spokeswoman declined to comment on whether the new unit was related to client conflict issues. She also declined to confirm whether the staff for the Daimler team would be from one of the group’s existing agencies.
Dr Jens Thiemer, the head of brand communications for Mercedes-Benz Cars, said: "With the current growth strategy 'Mercedes-Benz 2020' in mind we have optimised our activities in the media field.
"Our concern is for consistent, innovative marketing communications that lead in quality, for still greater efficiency in media planning, and above all an answer to the global challenges presented by digital media."
Sources suggested the review was triggered by staff changes in the procurement team at Mercedes.
In October 2012 Maxus was behind the "#youdrive" campaign in the UK, which allowed TV viewers to decide how an ad for the Mercedes A-Class vehicle would end by voting through Twitter.