See the linked URL. First message should certainly have suggestions.
Given that Special:SearchTranslations works, it looks like the database was emptied at some point and not repopulated.
Version: unspecified
Severity: major
URL: https://meta.wikimedia.org/w/index.php?title=Special:Translate&group=page-Tech%2FNews%2F2013%2F31&filter=&action=translate&language=fr
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=51956
https://bugzilla.wikimedia.org/show_bug.cgi?id=52277