Revenons à nos moutons: means Let's go back to our subject. And it's used when we are out of the discussed subject. In arabic: لنعد لموضوعنا

You would typically use it after you've digressed and would like to get back to the previous topic of discussion. :)

Nos moutons = our affairs= Business Nous avons parlé des problèmes du voisins maintenant revenons à nos moutons. Classique expression un peu vieilles...