I have transcribed two documents from SHD 16 N 1522 this morning and posted them.

The first is a list of "inscriptions"--which I would translate as "graffiti"--written on the sides of leave trains, presumably by soldiers. The document catalogs the inscriptions on five trains--R, R bis, R ter, L, and 2B--leaving Paris's Gare du Nord for the Champagne region on 29-30 June and 2-3 July 1917.

A quick quantitative review:

Number of inscriptions: 60
% of inscriptions with a clear anti-war message: 53
% of inscriptions with any kind of pro-war message: 2
% of inscriptions critical of commanders/officers: 15
% of inscriptions critical of politicians/the government: 20
% of inscriptions using socialist language: 7
% of inscriptions calling explicitly for revolution: 17
% of inscriptions critical of the church/clergy: 3
% of inscriptions critical of shirkers/non-combattants: 25

I find four things to be surprising:

There was one clear pro-war inscription. It reads: "The Boches are murders of women and children. [They deserve] reprisals!" This inscription could suggest that hatred of the Germans and a desire for revenge could co-exist in the same discursive space as a hatred of Poincaré, Nivelle, the Church, and the war itself. Anti-war and anti-German messages were not mutually exclusive. But it is impossible to know this for sure, as the report does not indicate whether all the inscriptions appeared to be the work of the same person. It may be that one poilu felt compelled to write something "patriotic" after he saw how "unpatriotic" the other inscriptions were.
Three inscriptions were explicitly royalist. Two others read: "Down with the Republic, long live the King!" Another reads: ""Long live the King, long live the Pope, down with the Republic, long live France!" I am not entirely sure what to make of this. It may have been sarcastic, or it may suggest a disillusionment with the Third Republic. That these three inscriptions came on different trains--two on Train R and Train R bis--that travelled along the same route and that the two found on Train R are exactly the same could indicate that somebody who either worked or was stationed along this route put up the message.
There is a relatively low number of explicitly socialist (7%) or revolutionary (17%) messages, which stands somewhat in contrast to the language used by mutineers at the front during May and early June.
Although the messages that were anti-civilian/gendarme/non-combattants (i.e. directed at "vaches," "embusqués," as well as "gendarmes") came to only 25%, the language in these messages was terse and violent, nearly always calling for "mort aux -----."

The second is a somewhat lengthy report as to the causes of collective indiscipline, both at the front and in train stations.

What I find puzzling about the report is the double-think that the author seems to employ. He argues that the mutinies were spontaneous reactions to conditions at the front and disappointment with the Nivelle Offensive but at the same time holds that the mutinies were simply weak echoes ("ricochets") of strikes and labor unrest in the rear among the working class. He notes further that there is no evidence of a functional relationship between pacifists in the rear and mutineers at the front. In other words, he concedes that the evidence demonstrates that the mutinies had nothing to do with pacifism, revolutionary socialism, or working class identity among soldiers. Nor were they the product of the infiltration of the army by pacifist rabble-rousers or mischief-makers. Yet, he still believes that the mutinies were--somehow, some way--caused by people other than the mutineers themselves. I am not sure if this position is a function of the officer's desperation to absolve the army of any fault or his inability to admit that simple soldiers could act as political agents. It is also possible that he intentionally provides commanders with the answer they want to hear, but then consciously undermines his own point in order to suggest that this answer is faulty.