Whereas in the second half of the nineteenth century the almost absolute control of academic institutions over the arts was questioned in both France and England, especially by the Academy of Fine Arts and the Royal Academy, “salonnets” and private galleries proliferated on both sides of the Channel. The French artist Edgar Degas (1834-1917) and his American-born counterpart and friend James McNeill Whistler (1834-1903) were deeply involved in the new exhibition spaces flourishing at that time on the margins of the official salons. Such events as the setting up of “impressionist” exhibitions in Paris (1874-1886), the opening of the Grosvenor Gallery in London (1877) and/or individual exhibitions in both capital cities, gave them many opportunities to act as mediators of contemporary art – which they may have been predisposed to thanks to their two different cultures. In fact, these two strong, independent personalities shared an early awareness of the value of "staging" their works in order to highlight the aesthetic qualities of profoundly innovative creations. Actually, when faced with works that were no longer pastiches of antiquity or of historical, biblical and mythological subjects, spectators in those days often saw, at best, only an assemblage of colours and forms that they considered "unfinished". In order to direct their attention towards the importance of the material characteristics of their works, and to prove that they were more than just anecdotal curiosities, Degas and Whistler almost simultaneously created mediation "tools”. From the posters advertising their exhibitions to the colour schemes on their walls, from the frames of their works to the catalogues that referred to them, the museographic innovations they imagined were a milestone in the history of art. They are here put into perspective, particularly in relation to the evolution of the history of taste, the circulation of models, networks of sociability, collections and the art market, and especially to the way they participated in the cultural transfers that bore the hallmark of the internationalisation of art at the dawn of the 20th century. My presentation shows how these new museographic media, if they play a decisive role in the appreciation of the works and are evidence of intuitions shared across borders, also reflect specific ambitions, partly linked to their cultural differences.