Where officers from the Nazi’s armed forces used to gather during World War II, Hamburg’s upper class can now buy a luxury apartment in a complex that includes a gym and yoga studio, four saunas and a lounge co-designed by the renowned Karl Lagerfeld.From the front, the building erected in 1936 – with its metre-high columns framing the entrance and two large eagles on the roof – looks out of place among the neighbouring designer houses and big mansions.The building is one of several across Germany with Nazi ties that have been turned into luxury properties where critics say not enough is being…