(Reuters) -Remy Cointreau on Wednesday named Frank Marilly as its new CEO, tasked with leading the French cognac maker through a period of spiralling sales and tariff threats in its key U.S. and Chinese markets.

Marilly, 59, who has worked in luxury and cosmetics groups including Chanel, Unilever and Japan's Shiseido, will take office on June 25, replacing Eric Vallat, who resigned earlier this year after more than five years at the helm.

Vallat will work alongside Marilly to ensure a harmonious transition, the statement said, adding Marilly had successfully navigated "high-stakes" environments in his previous roles and was a strategist with the ability to "unite and transform".

"We are convinced that he (Marilly) will bring a new dynamic and will be able to confidently address the new challenges of the group's growth in a complex macroeconomic and geopolitical context," Remy Cointreau Chairperson Marie-Amelie de Leusse said in a statement.

Remy Cointreau makes 70% of its sales from cognac, the vast majority of which is sold in China and the United States. This has left it more exposed to the tariffs than some competitors with a broader geographic reach or product portfolio.

China has already imposed steep levies on brandy imports from the European Union as part of a trade dispute with Brussels. The U.S., meanwhile, is also threatening hefty duties.

Sales in both countries have also come under pressure amid a sluggish Chinese economy and high interest rates and inflation in the United States, where Remy's rivals have been cutting prices and taking market share.

Marilly said in a statement he would leverage his experience to pursue Remy's strategy based on cultivating the value of its high-end brands.

"Together, we will continue to accelerate the group's development, capitalizing in particular on the excellence of its know-how and its capacity for innovation, while meeting the expectations of a constantly evolving sector," he said.

(Reporting by Mathias de Rozario in Gdansk, Dominique Vidalon in Paris and Emma Rumney in London; Editing by Christian Schmollinger and Jan Harvey)