On War (French: De la guerre) is a 2008 French comedy-drama film directed by Bertrand Bonello and starring Mathieu Amalric, Laurent Lucas, Guillaume Depardieu, Asia Argento, Michel Piccoli and Léa Seydoux. It follows a man in the middle of an existential crisis as he gets drawn into a strange pleasure-obsessed cult. The film's title loosely refers to the treatise On War, by Carl von Clausewitz.