This is affirmative (.), rather than interrogative (?):
- a-t-on appris que ? (Did learn that/if?)
- (), a-t-on appris récemment. (..., so we learnt recently)
Such a figure of speech, when handled carefully, with the correct intonation, may express different shades. First, it may sound more literary, yet more or less neutral as in your example. But it can express surprise, amusement, especially when you are face-to-face which the person you have just learnt something about.
Tu apprends le français, m'a-t-on dit...
Generally, such a sentence indirectly asks for an answer, as if it was a question.