War games: the strange story of Léon Gimpel and the Parisian street kids

Tucked away in a dark room in the Église des Frères Prêcheurs in Arles, next to a much bigger exhibition of first world war monuments by Rayond Depardon, is a small show of a series of autochromes by Léon Gimpel.

Entitled Kids at War, it is one of the most intriguing shows at this year's Rencontres d'Arles photo-festival.

Though not as well-known as his contemporaries, Atget and Lartigue, Gimpel, as this show illustrates, was one of the most restlessly mischievous presences in photography during the belle epoque. He created various experimental series, such as his early self-portraits taken in distorting mirrors, and his so-called "spirit photos", in which he manipulated light to create haloes and auras around his sitters.

Kids at War, though, is a true oddity. In 1915, Gimpel befriended a bunch of children who daily played war games on Rue de Grenata in Paris, recreating – in their makeshift way – the battles that raged across Europe. Every Sunday, Gimpel arrived with his new colour camera and orchestrated the kids, helping them create their often exotic military costumes and make wooden rifles, bayonets and even an aeroplane, which he hung on ropes from a lamppost. Look closely and you can see that its component parts include a coffee grinder and a broom handle. Above it, a cut-out of a German plane hovers.

Gimpel's small autochromes of these staged tableaux are both innocent and knowing, and, here and there, disturbing in their mirroring of reality. In one image, ominously titled Execution of a Boche, he stages a strange firing squad in which one boy stands blindfold before the mouth of a large cannon made from a piece of metal pipe. Another child, in a naval uniform, holds a pretend rifle pointed at the victim's heart.

Elsewhere, the images are more playful. An angelic-looking boy is decorated by a stern-looking officer, while a ragtag bunch of children, including a nurse and two bandsmen, stand to attention. In the left foreground, a tiny child with a pot belly stares defiantly at the camera.

This is a boy called Pepete, whom Gimpel described as "small, slightly misshaped, rather scrofulous, looking like a gnome". What is interesting here is how much the children enjoy becoming a part of his elaborately staged shots. In another black-and-white photograph, The Charge, they stride towards the camera, guns and swords at the ready, while a crowd of bemused adults look on, smiling.

That Gimpel's Jewish family fled Alsace during the German advance lends the images another layer of meaning. The images are unreal, not only in their staging, but in their evocation of heroism and glory. Save for the firing-squad tableau, the enemy are seldom seen and death remains an abstraction. In the semi-darkness of a room in the Église des Frères Prêcheurs, the images exert a strange fascination. They seem, in their smallness, and in the world they evoke, to be strange fictions from the pioneering days of image-making. Every Sunday, at the end of the day's action, Gimpel handed out sweets to his battle-weary troops. They gathered around him, shouting "Vive le Photographe!"