German director Florian Gallenberger. [Photo provided to China Daily]

He has directed only three features－Shadows of Time (2004), John Rabe and Colonia (2015)－but he has received wide acclaim.

For Gallenberger, China is not a strange place as he spent two years in the country shooting John Rabe, a biopic of a German businessman who sheltered more than 200,000 Chinese during the Nanjing Massacre.

The nonstop slaughter from December 1937 to January 1938 saw more than 300,000 Chinese killed by Japanese troops in then-capital of Republic of China (1912-49).

"I know that for Japanese culture it's very difficult to face guilt and shame," says Gallenberger while speaking about John Rabe's ban in Japan.

But he is glad that the film,with a three-hour television version released in Germany, made more Germans aware of history.

"Millions of people have watched the film. I think it has brought about some changes in them," he says.