Alfred —, French army officer whose imprisonment for treason in 1894 raised issues of anti-Semitism (7)
I believe the answer is:
dreyfus
(Other definitions for dreyfus that I've seen before include "Frenchman involved in affair" , "French captain, wrongly convicted 1894" , "French army officer" , "- Affair, in which Zola was involved" , "The - Affair in France concerned a wrongly imprisoned officer" .)