blank page when trying to create smart group in French

following this how to : http://book.civicrm.org/user/current/organising-your-data/smart-groups/ I tried to create a new smart group. After selecting "create new smart group" I got a blank page ( design of my current wordpress admin page but with only header and footer, and no form to enter a name for the smart group)

as a workaround selected english as localization, and i was able to create a new smart group.
then i guesse there is some error in the civicrm.mo for fr_CA at least . Maybe an unprotected " ' ".