1. A method of classifying a multimodal test object termed a multimedia test object described according to at least one first and one second modality, characterized in that it includes a step of offline construction by unsupervised classification of a multimedia dictionary (W m ), defined by a plurality K m of multimedia words, on the basis of a recoding matrix (X) of representatives of the first modality forming a dictionary of the first modality including a plurality K T of words of the first modality, the recoding matrix (X) being constructed so that each of the components thereof forms information representative of the frequency of each word of the second modality of a dictionary of the second modality including a plurality K v of words of the second modality, for each word of the first modality, the classification of a multimedia test object being performed online by means of a step of recoding each representative of the first modality relating to the multimedia object considered on the multimedia dictionary (W m ) base, followed by a step of aggregating the representatives of the first modality coded in the recoding step in a single vector (BoMW) representative of the multimedia object considered.