Southern France has certainly seen its share of religious conflict and civil warfare. My own research explores violence in the French Wars of Religion of 1562-1629, especially focusing on the latter stages of those conflicts.
Larry Marvin, one of my friends from graduate school at the University of Illinois at Urbana-Champaign, has published a military history of the Albigensian Crusade, a major conflict fought in southern France during the medieval period:
Laurence W. Marvin, The Occitan War: A Military and Political History of the Albigensian Crusade, 1209-1218 (Cambridge: Cambridge University Press, 2008).
The book was just reviewed on H-France by David Stewart Bachrach, who writes: “This highly accessible work is a benchmark for the writing of military and political history on the regional level.” The review is glowing, stating that “the great achievement of this text is to interweave military history into the broader patterns of medieval society in which wars were fought.” Bachrach concludes that “all future discussions of the Albigensian crusade will have to begin with this study.”
Congrats to Larry!