Before teaching at the Pensionat von Neuwelcke School for girls in France (pictured above), Emilie Sagee had taught at eighteen different schools. Eighteen schools from which she had been fired because of the phenomena that accompanied her. This 32-year old school teacher and her ability of bilocation has become one of the most witnessed and documented cases of a Doppelgänger in recorded history.
Although the word, Doppelgänger, did not come into use officially till the mid-19th century, there have been references to the phenomenon in ancient mythology and all the way through to contemporary literature. And, while real-life instances are almost non-existent now, we have plenty of historic cases like this one. Find a few more well-known ones at the Wikipedia entry. A very interesting literary and cinematic storytelling device too.