British Airways currently sells tickets around 450-490€ from several German airports to Cape Town (South Africa). Basically every airport served by British Airways works. This is a pretty good fare since this is peak season in South Africa and less than 20hours travel time with you a single stop in London.
The best prices are available from Hamburg and including an airport change in London.
Hamburg – Cape Town with airport change: HAM-CPT 454€
Berlin – Cape Town with airport change: TXL-CPT 467€
Hamburg – Cape Town: HAM-CPT 480€
Berlin – Cape Town: TXL-CPT 487€