I deleted an e-mail by mistake: how do I find it again?
A deleted e-mail goes to the Corbeille (Trash) folder of its mailbox.
Step by step
In Mail, click the Corbeille (Trash) folder.
Open the message.
Click Déplacer vers un dossier (Move to a folder) (above the message, on the right), then Boîte de réception (Inbox).