PARIS (Reuters) - U.S investment company Artisan Partners on Wednesday said that Danone needed to appoint a new, independent chairman, adding more pressure on Emmanuel Faber who holds that position at the French food company. This week, Danone said Faber - who until now has combined the CEO and chairman roles - would stay on as chairman and oversee the search for a new chief executive. “With Mr. Faber as chairman, the incoming CEO will not have the appropriate latitude to set a new direction,” wrote Artisan, which has a stake of around 3% in Danone. Artisan Partners’ letter to Danone’s board of management echoed a similar position from investment company Bluebell, which also said Danone should appoint another independent chairman instead of Faber. Activist investors say Danone - whose brands include Evian and Actimel - needs a management revamp as they believe that under Faber’s tenure, Danone’s sales growth, margins and share price have lagged rivals, including Perrier-owner Nestle and Unilever, the maker of Cornetto ice cream and Lipton tea.