It's a drama set in Paris, France, beginning in May 1941 and extending into late 1942. It follows the story of a Jewish-owned jewelry shop after the Germans have taken over Paris.
Joseph Haffmann (Daniel Auteuil) is a successful middle-aged jeweler of great skill. When he sees signs stating all Jews need to report for a census, he sends his wife and three children to a safer area in Vichy France. François Mercier (Gilles Lellouche) is Haffmann's recently-hired French assistant. Mercier is an unhappy man who could not serve in the army because of a bad leg that requires a brace. He is also despondent because, after several years of marriage, he cannot have children with his wife, Blanche (Sara Giraudeau). The doctors have indicated Blanche is healthy, so François blames himself.
Haffmann concocts a scheme to save his business during the German occupation by "selling" it to Mercier, with the understanding he will repurchase the shop after the war. He promises to help Mercier then set up his own shop. Mercier agrees though Blanche is skeptical. However, Haffmann is foiled in his efforts to follow his family and is forced to hide with the Merciers, who have already moved into Haffmann's home above the shop.
The film then follows the difficult changes in the relationship between Haffmann and the Merciers, especially since a German Commandant named Jünger (Nikolai Kinski) becomes a major customer of the store. Relationships deteriorate until a surprise allows for a righteous ending.
"Adieu Monsieur Haffmann" is perhaps the best film I've seen this year. The acting, direction, and cinematography, are all excellent. The righteous ending seems a little improbable and subtracts my rating from a 10 to a 9. The viewer gets into the souls of the three principal characters. The film is derived from a play, so almost all the action takes place in one building. Highly recommended.