A Very Long Engagement

A Very Long Engagement is a 2004 French film set in the early twentieth century. Mathilde (Audrey Tautou) was engaged to her childhood sweetheart Manech (Gaspard Ulliel) when he was enlisted to fight in the war. Manech tried to get excused from duty by getting his hand shot, but he was instead convicted of self-mutilation and left to die with four other soldiers in the no-man's land between the French and German trenches. Mathilde, however, refuses to believe that Manech is dead, and sets out on a mission to find him. Along the way, she meets people who are also connected to the five condemned soldiers, and learns their stories.

Tropes used in A Very Long Engagement include:

Best Served Cold: Tina Lombardi's vengeance.
Bittersweet Ending: Mathilde finally finds Manech, who is alive and well physically, but has lost all memories of his life, including those of her and of their relationship. However, it's hinted they restart from the beginning, and the doctors also imply he might eventually regain the memories he's lost.
Book Ends: "Ca te fait mal quand tu marches?" ("Does it hurt when you walk?") The first time is not at the beginning of the movie, but at the beginning of Manech and Mathilde's relationship.
Dodge the Bullet: Benoît Notre-Dame miraculously survives two direct hits from bombs.
Dwindling Party: The fates of the five soldiers are revealed slowly as the story unravels.
Easy Amnesia: Played with. We don't know what exactly caused the amnesia, so a realistic cause is possible. However, both procedural and declarative memory seem to be affected ("He even had to learn to read and write again.").
Fan Service: Audrey Tautou, in a few scenes. In one in particular, she looks like she should be riding a clamshell.
Femme Fatale: Tina Lombardi to a tee; a prostitute who goes about assassinating the people involved with the death of her boyfriend and ruthless procurer.
Give Me a Sign: Mathilde makes a number of bets with herself, believing that if events go in a certain way that she predicts, it will be a sign to not give up.
I Will Find You: The driving force of the plot.
Jerkass: The officer who ignored Poincaré's pardon and sent the soldiers into no-man's land.
Keep the Home Fires Burning
Kill'Em All: The scenes where the poor French soldiers go over the top and are completely obliterated by machine gun fire within seconds.
Lost in Translation: The three M's, in French, stand for "Manech aime Mathilde" (aime, which means loves, sounds like the letter M). This carries over into English as "Manech's marrying Mathilde".
Ludicrous Gibs: A horribly realistic version, with one soldier showered with the giblets of another after he gets blown up by a grenade.
Meaningful Echo: The Book Ends, "Does it hurt when you walk?"
Meaningful Name: Germain Pire, "pire" means "worse" in French. The character's catchphrase in French is "Pire que la fouine" (worse than weasel), to show how his private investigator activity is serious business.
Mood Whiplash: A love story shot in sepia-tinted color that continually cuts to scenes of unbearable brutality.
Obfuscating Disability: Mathilde occasionally plays up her polio to put others at a disadvantage.
Punny Name: Referring to Mathilde's four-year separation from her fiancé Manech, and the war itself.
The Scrounger: Célestin Poux, famed throughout the rank and file for pulling various stunts in order to keep the troops supplied with food.
Shot At Dawn: Notably averted; instead of being shot for cowardice, the five soldiers are sent out in to No-Mans Land to either starve or be shot by the Germans. Ange Bassignano ends up shot in the back by a French nationalist officer after having verbally denied his French nationality to stay alive.
War Is Hell: A French film, set on the Somme, about a war where France lost 9% of its male population and left untold thousands crippled and emotionally scarred? You bet it's hell.
World War I: Shown in flashbacks.