Here is information I have so far found on this individual.
If anybody has more of his texts concerning Macedonians, please share, I have been unable to locate anything more elaborate thus far.
http://en.wikipedia.org/wiki/Henri_Barbusse
Henri Barbusse (May 17, 1873, Asnières-sur-Seine—August 30, 1935, Moscow) was a French novelist and a member of the French Communist Party.
Henri Barbusse (May 17, 1873, Asnières-sur-Seine—August 30, 1935, Moscow) was a French novelist and a member of the French Communist Party.

One is truly speaking here of a nation. A nation which has its own original ethnic character, its traditions, its aspirations, its unique and specific personality….
La question macedonienne est-elIe si complexe que cela ? "Fe de ration Balcanique" No.51, November 1, 1926
La question macedonienne est-elIe si complexe que cela ? "Fe de ration Balcanique" No.51, November 1, 1926
The Macedonians, who have their own separate language and indisputable ethnic originality, do not have the right to be called Macedonians…
Un peuple asservi, "Monde" No.108, June 28.1930
Un peuple asservi, "Monde" No.108, June 28.1930
http://www.h-france.net/rude/2005conference/Drapac2.pdf
Commentators concentrated on the nature of the Marseille killings almost to the complete exclusion of an analysis of the possible reasons for the assassins’ recourse to extreme behavior............A pamphlet which fulminated against the Macedonian separatists and their role in the assassination, quoted from Henri Barbusse’s vigorous 1928 denunciation of IMRO. He, like others after him, noted the “absolutely indisputable” fact of “the collusion of autonomists with fascism,” but wrote nothing of the treatment of Macedonians in the successor state.
Commentators concentrated on the nature of the Marseille killings almost to the complete exclusion of an analysis of the possible reasons for the assassins’ recourse to extreme behavior............A pamphlet which fulminated against the Macedonian separatists and their role in the assassination, quoted from Henri Barbusse’s vigorous 1928 denunciation of IMRO. He, like others after him, noted the “absolutely indisputable” fact of “the collusion of autonomists with fascism,” but wrote nothing of the treatment of Macedonians in the successor state.
If anybody has more of his texts concerning Macedonians, please share, I have been unable to locate anything more elaborate thus far.