1. A method of assisting with the construction of a tree of clusters of electronic documents, which documents are defined by predetermined attributes, wherein the method comprises, for a given cluster of documents and a given level of the tree, the steps of: a) obtaining and storing constraints defined by a user between at least two documents of said cluster, each of said constraints specifying a linking relationship between at least a first document and at least a second document of said cluster, said linking relationship indicating whether the first document and the second document must be or cannot be included in a same subcluster; b) constructing subclusters as a function of the constraints obtained and the attributes of the documents of said cluster, said subclusters comprising all the documents of said cluster; c) creating a tree level corresponding to the constructed subclusters; and d) selecting a constructed subcluster and iterating the steps a), b), c), and d) for the selected subcluster to obtain said tree.