Any ID for the rifle is appreciated
Source for title and description: https://imagesdefense.gouv.fr/fr/toilette-de-fantassins-de-l-infanterie-alpine-1.html

Belonging to the 14th Army Corps (Lyon), they were stationed in the Alps, alpinized and dressed in the regulations of the loose and dark beret (tarte), the blue woollen belt and calf bands.
Jean-Baptiste Tournassoud, assigned to this unit (1), probably asked them to pose and stage themselves in this way.

Notes:
Date and location are unknown. However, the author's assignment to the photographed unit makes it possible to situate the photo between August 1914 and November 1916, and the red trousers, gradually replaced by the blue trouser cover from 1915 onwards, constitutes another chronological clue.
(1) Jean-Baptiste Tournassoud was mobilised on 2 August 1914 in the 14th squadron of the Military Crews Train (14th ETEM) of the 14th army corps and served in section 1 of the administrative convoy (CVAD 1/14). On 7 April 1916, he was seconded to the staff of the 6th Army, geographical service. He served in the CVAD of the 14th ETEM from 27 April 1916 to 22 November 1916.
ECPAD is the holder of the economic rights relating to the autochromes made by Jean-Baptiste Tournassoud. These rights are in the public domain on January 1, 2023.