This article deals with the interest in and possibility of a history of French soldiers' relationship to time in World War I. It focuses first on the question of sources. It shows that accounts like personal diaries, letters and poems, indispensable sources for this type of history, generate powerful effects that must be taken into account. However, it seems necessary to question the existence or not of micro-regimes of historicities linked to war experience. The article shows that war experience at the front is also a particular experience of time in which an immobile time and projections into the future can occur together and sometimes contain great expectations. It also emphasizes the importance of apprehending war as a temporal parenthesis for the soldiers. It is possible that this relationship to time that the soldiers both undergo and work out themselves explains one of the reasons for their tenacity at the front.