(FILES) In this file photo taken on February 26, 2020 the CEO of Germany's Axel Springer media group Mathias Doepfner attends a stumbling stone (Stolperstein) laying ceremony in front of the headquarters of German publishing house Axel Springer in Berlin. - Mathias Doepfner, boss of Germany's Axel Springer, one of the biggest European media groups, has been forced to apologise after the publication of a series of controversial private messages triggered anger in its ranks. (Photo by Tobias SCHWARZ / AFP)