A method for locating, in a deposition line including a succession of compartments, an origin of a defect affecting a stack of thin layers deposited on a substrate in the compartments, in which each thin layer is deposited in one or more successive compartments of the deposition line and pieces of debris remaining on the surface of a thin layer deposited in a compartment act as masks for the subsequent depositions of thin layers and are the origin of defects, includes obtaining at least one image showing the defect, determining, from the at least one image, a signature of the defect, the signature containing at least one characteristic representative of the defect, and identifying at least one compartment of the deposition line liable to be the origin of the defect from the signature of the defect and using reference signatures associated with the compartments of the deposition line.