You've already answered this but since I've already typed it: one possible pitfall here is the automatic smart quotes feature of the OS X text system which may or may not be a factor depending on which programs are in use.  You can disable smart quotes in: System Preferences -> Keyboard -> Text -> Use smart quotes and dashes (this is on OS X 10.10).

But we really need more details to try to explain what you are seeing.  Can you give a step by step procedure on how to reproduce, including exactly what apps are being used (e.g. Terminal.app vs iTerm.app vs IDLE), and the results of the following commands in a terminal shell:

python3.4 -c 'import sys;print(sys.version)'
python3.4 -c 'import readline;print(readline.__doc__)'
env | egrep '(LC)|(LANG)'