Déja vu

Déjà vu: A disquieting feeling of having been somewhere or done something before, even though one has not. Although most people have experienced this feeling at some time or another, in certain people such sensations of déja vu are part of a seizure or migraine aura; while in others they are the seizure phenomenon itself.

Déjà vu in French means "already seen." See also Jamais vu.