This issue is specific to Mac OS X because the file system encoding is hardcoded to UTF-8 on this OS. As written in msg76244, the problem is that the encoding is different for input (sys.argv) and output arguments (arguments of child processes). As written in msg76255, program arguments are encoded to the locale (terminal) encoding.

Finally, the problem is that subprocess, os.exec*(), etc. encode command line arguments with the file system encoding instead of the locale encoding.

On Linux, it just work because the file system encoding is the locale encoding.