Direct characterization occurs when the author explains in full view what are the personality traits of the character. In this case, Mdme Loisel is a "very pretty" , charming, young woman.
In the story, she was directly described as:
The girl was one of those pretty and charming young creatures who sometimes are born, as if by a slip of fate, into a family of clerks. She had no dowry, no expectations, no way of being known, understood, loved, married by any rich and distinguished man.
Meanwhile, she is also described in the end directly as
Madame Loisel looked old now. She had become the woman of impoverished households--strong and hard and rough. With frowzy hair, skirts askew and red hands, she talked loud while washing the floor with great swishes of water. But sometimes, when her husband was at the office, she sat down near the window and she thought of that gay evening of long ago, of that ball where she had been so beautiful and so admired.
Indirectly, she is described by the reader and by the author by:
Speech: We know she complained endlessly about her situation, whined to her husband, was partially rude to him and dismissed any attention he had towards her.
Thoughts-She continuously dreams of bigger and better things. She imagines her humble dinner table as an opulent table where people eat trout and truffles rather than soup. She feels indebted to her friend and is willing to work to pay back the necklace, and she submits to a life of poverty.
Effects- She is like a nemesis to her husband, who had to endure 10 years of hard work and sacrifice, already after having sacrificed 400 francs to purchase a dress for her for this one ball. She has ruined their lives with her ambition.
Actions-Mdme Loisel through her actions showed that her sense of shame was too high. However, she set herself lose in the dance floor showing the reader the inner desperation she had to experience a life of luxury.
Looks-Mdme's looks became directly proportional to her life. She aged incredibly, looked worn out and provincial, lower than what she would've deemed as "low" and petty, catty, and disillusioned with life.
Direct: Mme Loisel was pretty, charming, and born to a family of artisans. She broght no money to her marriage. She like expensive and elegant things, though she could not afford them.
Indirectly: Mme Loisel complained often and was rude to her husband. She liked to imagine herself as a wealthy or rich person. Also, she often was embarrased by her clothing or living conditions and envied those of her richer friend.