The National Navy Buildings are currently threatened by a renewal project of the Defense Ministry. Indeed, a demolition authorization has been asked, without any preliminary expertise, and even though this is a significant patrimonial legacy of the 20th century. This valuable architectural ensemble, that holds a special place in Perret's work, represents a decisive stage in the elaboration of the "Ordre du béton armé". For John Summerson, this ornament free concrete building was thought in terms of orders; it has as much expression, rhythm and variety as the Garnier Opera, even if there is no moldings or sculptures. For Peter Collins, the care granted to the composition, the proportions, the game of light and shadow, reveals something deeper than an intelligent amelioration of essen-tial architectonic elements. Industrial architecture reaches here the highest degree of Art. The loss of the National Navy Buildings would deprive us of an essential link for the comprehension of Perret's heritage, which already suffered from the destruction of Ponthieu garage (1906) and Esders workshops (1919), and the severe mutilations of Amiens Station Square. Therefore, the National Navy Buildings must be saved and protected, as a totality. Today, only the Administrative Building, listed in the patrimonial Inventory, remains into the renewal project while the other buildings are demolished. We cannot accept any dismantling of this harmonious work, which would necessarily discredit the 20th century patrimonial protection policy held by Ministry of Cultural Affairs. HALT TO THE DEMOLITION OF ONE OF THE PERRET BROTHERS' MAJOR WORKS.