Louis Pergaud

The children of Ballydowse and Carrickdowse engage in battles where they cut of the buttons, shoe-laces and underwear of their captured opponents... (imdb)

War of the Buttons is a film directed by Yves Robert, about two rival kid gangs whose playful combats escalate into violence. The title derives from the buttons that are cut-off from the rival team's clothes as combat trophies. (wikipedia.org)

In the countryside of France, two groups of boys from the rural villages of Longeverne and Velran are in constant war against each other. Their war is a tradition that passes from father to son and without a motive but the rivalry between the peasants. Lebrac is coming of age and he has a crush on the girl Lanterne while his teacher Merlin offers the chance for him to have a better study in another village. (imdb)

Separated by an ancestral hatred, two small villages of the South see their infant population engaging in war, while the teacher of the first village and the mayor of the second love each other. (imdb)