Comment 1 for bug 1331194

I'm not a French speaker and I have no good way to verify what this should be, but the English sentence is

"You will be sent email requesting confirmation, to prevent others from gratuitously subscribing you."

I have played around with Google translate a bit and it seems that perhaps better than either of the above is

"Vous recevrez un courriel de requête de confirmation, cela empêche que
d'autres personnes vous abonnent impunément."