Macquart cycle, La Debacle (1892) takes as its subject the dramatic events of the Franco-Prussian War and the Commune of 1870-1. During Zola's lifetime it was the bestselling of all his novels, praised by contemporaries for its epic sweep as well as for its attention to historical detail.

La Debacle seeks to explain why the Second Empire ended in a crushing military defeat and revolutionary violence. It focuses on ordinary soldiers, showing their bravery and suffering in the midst of circumstances they cannot control, and includes some of the most powerful description Zola ever wrote. Zola skilfully integrates his narrative of events and the fictional lives of his characters to provide the finest account of this tragic chapter in the history of France. Often compared to War and Peace, La Debacle has been described as a "seminal" work for all modern depictions of war.