In your the plugin folder (gravityforms) there should be a language folder, and in there a gravityforms-fr_fr.mo file.  Can you check for that please?
If it is, the issue is likely due to the different naming conventions.  The plugin uses fr_fr but you are using fr-FR.  I believe those two need to match.  You could symlink the file included with Gravity Forms to one in a format to match your language setting.  From a command line, you could do this.
[/var/www/public_html/wp-content/plugins/gravityforms/languages]$ ln -s gravityforms-fr_fr.mo gravityforms-fr-FR.mo
Posted 13 years ago on Monday October 1, 2012 | 
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