OK, thanks, now we're getting somewhere!  From the pathname (/opt/local/bin), I assume you are using the Python 3.4 from MacPorts and from the readline docstring that Python 3.4 is linked with BSD libedit rather than GNU readline.  MacPorts supplies its own, newer version of libedit rather than the Apple-supplied one shipped with OS X.  It looks there is something funky going on there such that the pasted characters are being edited. The python.org Python 3.4 links with the older system libedit and it does not display this behavior.  It could also be due to a patch in the MacPorts Python 3.4 or libedit.  In any case, there seems to be an easy workaround: have the MacPorts Python use GNU readline instead.  You can do that by running:

sudo port py34-readline

I'll leave this open to investigate further later, assuming the workaround works for you.