Metz St-Stephen cathedral concentrates in every respect the aspects of the eventful history of Moselle. Built over nearly three centuries, the cathedral undergoes major alterations in the middle of the 18th century : its original surroundings disappear in favor of an urban development perfectly arranged and designed by Jacques-François Blondel. The 19th century imprints a deep mark on the monument: the French gradually remove the classical style additions and isolate the monument from its urban context. In 1871, the cathedral is integrated to the German Empire. The building goes through a profound restructuration own to tremendous financial means and William II of Prussia’s new political ambitions. Appointed as Dombaumeister in 1874, the Prussian architect Paul Tornow promptly establishes a huge project for Metz. In thirty-two years, he completes the restoration of almost the whole building and manages three major works which will alter it deeply : reconstruction of the roof, restoration of the gate of the Virgin Mary and the creation of the main entrance. In spite of his dedication to the monument for many years, the architect will not be able to see his projects of spires on top of the Chapter Tower and over the crossing according to his idealized view of the medieval cathedral. This research highlights the achievement of the works, completed or not, by Paul Tornow on Metz cathedral. Amidst a tense geopolitical context, the Prussian architect did not attempt to germanize the cathedral but rather establish a closer connection with the leading examples of French medievalmodels of the 13th century.