The agency appointment, made after a pitch involving two other unnamed shops, is a prelude to a TV and print campaign due to break later this year. Media is being handled on a local market basis and budgets are undisclosed.
The assignment builds on an existing relationship between Mercedes and Scholz in Berlin, which already handles some of the automaker's truck business.
Unveiled at the Frankfurt Motor Show in September last year, the Vaneo, like the Citroen Berlingo and Renault Kangoo, was developed initially as a light commercial vehicle. But growing demand for so-called multispace vehicles has led Mercedes to introduce a people carrier first.
It is aimed at bringing new recruits into the Mercedes fold, particularly in the UK, where research has shown that buyers value a prestige badge.
The company believes there is huge potential for the car. European sales are expected to grow from 486,000 vehicles in 1999 to 710,000 in 2003.
Daniel Floyed, the managing director of Scholz in London, said: "Berlin has a very good creative reputation to which we give an extra edge. We always seem to get a good end result when we work together."