On the eve of the First World War, he made quite an impression as part of M. Druet's "First Group." As noted by the "Burlington Magazine for Connoisseurs", the exhibition was "chiefly remarkable for a series of paintings or drawings - it is hard to say which - by M. Hermann-Paul in a new medium which is simply ripolin." The Great War soon intervened and Hermann-Paul would document its tragedy as well as its foibles. After the war, he underwent several stylistic changes. In his later years, he produced many works in dry point and ink depicting his beloved Camargue.