This paper is focused on intensive comparative structures (which are by far the most numerous in language and discourse) applied to the adjective negro in mediaeval Spanish. Many examples are studied and connected to similar structures in Mediaeval French (Old French and Middle French). The concept of collocation used in this paper is based on the same concept developed within Explanatory and Combinatorial Lexicology. The examples which contain the above-mentioned comparative structures are taken from the CORDE (Corpus diacrónico del español, RAE) and CDH (Corpus del Nuevo diccionario histórico del español) corpora. All the second terms of this type of comparison are specified and discussed, from the most frequent (pez, carbón, cuervo...) to the least frequent (olla, diablo, guijarro, escarabajo...). It is found that even if Spanish and French are very similar regarding the use of collocative items (which is partly due to phraseological borrowings, as a result of the bustle of translating activity at that time), there are also clear divergences between the two languages. Thus, noir comme l'encre, which was very common in Mediaeval