André and Louise (Boyer and Darrieux) are a general and his countess living in France sometime around the end of the 19th century. Whatever intimacy they may have once shared in their marriage is definitely gone, but they seem to have settled into an amicable friendship. Louise is in debt because of...something, so, needing cash, she sells some lavish diamond earrings that were a present from André. To cover their disappearance she claims that they were stolen. The jeweler is uncomfortable hearing this, and goes to André, who buys the earrings back. He doesn't tell Louise, though, instead giving the earrings to his mistress.
The mistress goes on a vacation to Constantinople, gambles all her money away, and sells the earrings. They are bought by Donati, an Italian diplomat posted in Paris (de Sica). Donati meets Louise and they fall in love. Donati, unaware of the origin of the earrings, gives them to Louise as a present. Louise, unaware that André knows her secret, contrives to "find" them.
Charles Boyer was a Frenchman who had come back to the French film industry after two decades starring in Hollywood. Vittorio de Sica is better remembered as a film director, who helmed a host of classics, including Bicycle Thieves and Two Women.
- At the Opera Tonight: Louise fakes losing her earrings when she and André go to the opera so as to avoid having to explain that she sold them.
- Call-Back: In the beginning, foolish, flighty Louise goes to a church to pray that the jeweler buys the earrings. At the end, a much more serious Louise goes to that same church to pray for Donati's life.
- Chick Flick: A Melodrama about a middle-aged woman caught between her distant husband and her exciting, passionate lover.
- Cock Fight: André demands a duel with Donati, officially to defend the honor of the French army, but it is clear that the real reason is that he is jealous of Louise's love for Donati.
- Contrived Coincidence: Donati picks up some earrings in Constantinople, then, of all the women in France to meet and fall in love with, he picks the woman who used to own them.
- Crazy Jealous Guy: Even if he seems not to love Louise any more, André becomes one when he realizes that she really loves Donati and he demands a duel with him.
- Dances and Balls: A fancy dress ball is the scene of André's confrontation with Donati.
- Dance of Romance: The fact that Louise progressively falls in love with Donati is showed in a sequence where they dance together in different places.
- Dead Sparks: They aren't hostile or bitter or anything. But it is quite clear that whatever romantic feelings that André and Louise felt for each other is dead. André at least seems to feel bad about this, saying towards the end after finding out about her affair that he doesn't like the role Louise has put him in.
- Defrosting Ice Queen: In the beginning, Louise is frivolous and does not think that she could fall in love. Still, she progressively falls in love with Donati, to her own surprise.
- Downer Ending: Donati is killed, and Louise dies of a heart attack.
- Duel to the Death: Louise acquiring the earrings once again drives André to demand a duel with Donati. As the offended party, André shoots first, and as Louise rushes to stop the duel, she hears André's shot... followed by silence, implying that Donati is dead.
- Dutch Angle: Used repeatedly during the tense confrontation where André presents Donati with the earrings.
- Everything's Sparkly with Jewelry: Louise's diamond earrings are an important plot device. Other jewels are also important, like the precious ones she sells to buy back the earrings.
- Fainting: Louise pulls this trick from time to time, like when the jeweler is hesitant about buying the earrings, or when she's seeking to defuse a confrontation between André and Donati.
- The Film of the Book: The film is adapted from Madame de..., a 1951 book by Louise de Vilmorin.
- Foreshadowing: Louise faints several times. In the end, she faints one last time and she dies from a heart attack.
- The Hero Dies: The protagonist, Louise, dies from a heart attack in the end.
- High-Class Glass: André, being a count and a general in the army, affects one of these.
- High-Class Gloves: Besides being decorative, they're a plot point. After getting the earrings back from Donati, Louise pretends that she accidentally dropped them in one of her gloves. This tips off André that Louise has a lover, as he recovered the earrings after her initial attempt to sell them and gave them to his mistress, Lola, as a farewell gift.
- Latin Lover: Donati is an Italian diplomat and he is very bold when he tries to charm Louise.
- Love Triangle: Louise is married to André. They do not seem to love each other any more, but when Louise falls in love with Donati, André gets very jealous.
- Match Cut: As part of their Falling-in-Love Montage, there are a series of match cuts from Louise and Donati dancing to—Louise and Donati dancing in a different place, each time with Donati bemoaning how long it has been since they last danced together (an amount of time that gets shorter with each dance).
- The Mistress: Lola is André's mistress. She breaks up with him and goes to Constantinople.
- Murder the Hypotenuse: André kills Donati, his rival for Louise's love, in a duel.
- No Full Name Given: The title lampshades that André and Louise's last name is never given in the film. One time the scene cuts while Louise is telling her name, one time someone forgets her last name, and two different times their name on a card is concealed by a piece of scenery.
- Officer and a Gentleman: General André de... is a nobleman and a cultured, refined, polite officer with a strong sense of honor.
- Old Retainer: Nounou, an old female servant, always takes care of Louise.
- Running Gag: André buying the earrings again and again. He did it once off screen. Then, he buys them again when the jeweller informs him that Louise sold them because she needed money. Later, after forcing Donati to sell them back to the same jeweller, he buys them for the third time. Finally, André gives them to a niece who sells them back to the jeweller. The jeweller immediately asks for an appointment with André, but this time he refuses to buy them. The jeweller does not understand why and he says that he has got used to selling these earrings to André.
- Sexless Marriage: Goes along with Sleeping Single. All the passion has long since gone out of André and Louise's marriage, ultimately driving them both to adulterous affairs.
- Sleeping Single: This wasn't mandatory in French cinema but it's appropriate here, since André and Louise are basically roommates rather than spouses.
- Star-Crossed Lovers: Louise finds her true love, but she cannot enjoy it. When she realizes that she is falling in love with Donati, she decides to leave Paris to resist her feelings. Finally, she decides to yield to passion and she comes back to Paris, but her husband André realizes that she is in love and he forbids Donati to meet his wife again. Finally, André demands a duel with Donati and kills him.
- Sympathetic Adulterer: André isn't mean or abusive to Louise. In fact he's quite friendly. But he seems to have lost all interest in her, and he's cheating on her. So it's romantic when Louise finds love with Donati.
- Tragic Hero: Ultimately, Louise's life collapses because of her initial flaw: she was a frivolous woman, only interested in jewels and clothes.
- Train-Station Goodbye: André's cheerful train station goodbye with his mistress contrasts with his rather frosty goodbye with Louise after he's found out about the earring switch.