He will depart at the end of the year.
Brown moves to a new role after 15 years as CEO.
Launch of Campaign Germany follows Canadian expansion earlier this year.
Publicis chairman and CEO speaks to Campaign at Q3 results and says the group is "winning in China", highlighting the robust media and creative performance across Asia-Pacific in Q3 results.
Organic growth tracks above 5% for a third quarter.
Group M veteran to join competitor group in October.
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