UPDATE 1-German retailer Douglas says CEO Mueller on medical leave

* Says not clear when CEO Mueller will return

* Says Mueller recovering from surgery

* Vanessa Stuetzle to join board as Chief Digital Officer (Adds background on pandemic, e-commerce push)

FRANKFURT, May 11 (Reuters) - Private-equity controlled German perfume retailer Douglas said on Monday its chief executive Tina Mueller would be on medical leave for an unknown period.

“Tina Mueller will be absent for the time being as she is undergoing medical rehabilitation following emergency surgery. At this time, it cannot yet be determined when she will be able to resume her responsibilities as Group CEO,” the group said in a statement.

The company - which started reopening stores last month after Europe-wide shutdowns due to the coronavirus pandemic - also said that Vanessa Stuetzle had been appointed as third member of the management board.

Stuetzle will take the role of Chief Digital Officer, joining the board alongside CEO Mueller and finance chief Matthias Born with immediate effect, Douglas added.

Mueller told Reuters in February that she was pushing to boost the group’s e-commerce business, especially in southern Europe where online offerings lack the customer acceptance levels seen in the German home market.

People close to the matter told Reuters in February that majority owner CVC Capital Partners was exploring options to sell or list Douglas. (Reporting by Ludwig Burger; Editing by Jan Harvey and Chizu Nomiyama)