At the declaration of the First World War Gutfreund was in Paris and decided to join the French Foreign Legion. He participated at the fighting on the Somme, at L'Artois and Champagne. In 1915 he applied to join the French Army and the following year had been imprisoned after his application was refused both for the French Army and the Czechoslovak Legion. He spent two years in a prison camp at Saint-Michel de Frigolet Abbey near Avignon. In 1918 he was moved to a civilian camp at Blanzy and after his release he settled in Paris to continue his work. For a short time he returned to Prague to accept a membership of the artistic group SVU Mánes.