Arguably. While it is true that the SPD has departed from its roots as a socialist working class party they can still be considered "leftwing". I don't want to go into too much detail here but Hannelore Kraft has run on a pretty leftwing platform of social policy (offering free childcare, as but one example).

When compared to american politics... pretty much every german party except maybe the FDP can be considered "leftwing" or even "socialist".