According to their current explanation, the Académie française proposes "Mél." (with period) only as an abbreviation for use on e.g. business cards, coined by analogy to the abbreviation "Tél." for telephone numbers. For usage in sentences they suggest either the full message électronique, or borrowing courriel from Québec, which they officially approved in 2003. http://www.academie-francaise.fr/la-langue-francaise/questio...

Mot-clic is humorous; I had not seen that before.