GDCMSeriesFileNames fails to read folder with non ascii characters

I’m having trouble with code that worked just fine for years. I’m trying to open a DICOM dataset from Japan and my code cannot see any files of the series folder.

The code is (with placeholders for seriesUID and patient name :

... 
auto seriesUID = "1.2.3.4"; 
seriesPath = "F:\\Data\\Images\\Pat_MAXXXXXX MIXXXX=丸山___=マル___\\Study_a1753f72\\Series_10b36a87";

typedef itk::ImageSeriesReader<itk::Image<short, 3>> t_ImageSeriesReader;
t_ImageSeriesReader::Pointer imageSeriesReader = t_ImageSeriesReader::New();

typedef itk::GDCMImageIO t_ImageIOType;
t_ImageIOType::Pointer imageIO = t_ImageIOType::New();
imageSeriesReader->SetImageIO(imageIO);

typedef itk::GDCMSeriesFileNames t_NamesGeneratorType;
t_NamesGeneratorType::Pointer namesGenerator = t_NamesGeneratorType::New();
namesGenerator->SetDirectory(seriesPath);
imageSeriesReader->ReleaseDataBeforeUpdateFlagOn();
imageSeriesReader->AbortGenerateDataOff();

imageSeriesReader->SetFileNames(namesGenerator->GetFileNames(seriesUID));
...

On the last line, GetFileNames() returns an empty list; but I can see I have multiple files in the folder.
When I rename the folder to remove the Japanese characters then loading works fine.

Is there something that I am missing here ? I am using (and kinda stuck with) ITK 4.13