Jančar won the prize for his 2010 novel "To noč sem jo videl" (I Saw Her That Night/Cette nuit je l'ai vue), which deals with the tragic World War II and post-war events in Slovenia, Delo reported on Tuesday.
French translations of eight of Jančar's books are currently available and his publisher Phebus said Cette nuit je l'ai vue would immediately be reprinted in 6,000 copies after the first print run of 3,000, according to the paper.
"I am happy, what else can I say…This means that I am somehow at home in a literary environment that I have always admired and that shaped me in my youth years," Jančar told the paper.
The prize, which will be handed out in Paris on 28 November, is just the latest recognition for Jančar.
At home he has won three Kresnik Prizes for best novel so far, including in 2010 for "To noč sem jo videl", as well as the Prešeren Prize for lifetime achievements, Slovenia's highest recognition for the arts, in 1993.
Jančar also won the European Short Story Award in 1994; the Herder Prize for literature in 2003, and the European Prize for Literature in 2011.