Mention users in Facebook replies

Click reply on a second level comment. choose the user you want to @mention

Step 1: Click on the reply that you want to answer

Step 2: Select the user in the dropdown that you want to @mention in your reply (the one you click reply on will be selected by default).

Step 3: Your reply will now contain a @metion of the user you replied to

OBS: You are only able to @mention users when replying to a second level comment (reply)