A Very Long Engagement (2005) on Netflix

Five desperate French soldiers during The Battle of the Somme shoot themselves, either by accident or with purpose, in order to be invalided back home. Having been "caught" a court-martial convenes and determines punishment to be banishment to No Man's Land with the objective of having the Germans finish them off. In the process of telling this tale each man's life is briefly explored along with their next of kin as Methilde, fiancée to one of the men, tries to determine the circumstances of her lover's death. This task is not made any easier for her due to a bout with polio as a child. Along the way she discovers the heights and depths of the human soul.