Michaud is like the lubricant for the machine of the novel. He's a retired police commissioner and an old friend of Madame Raquin. He also attends the Raquin's weekly Thursday gatherings. He plays a relatively minor role, but he is the figure responsible for breaking the news of Camille's death to Mme Raquin.
He also later convinces Mme Raquin that she should let Thérèse remarry. But Michaud's most important contribution to the novel is the scene in Chapter 10, when Michaud discusses how murderers often escape detection and get away with their crimes.
Because, you know, Thérèse and Laurent appear to get away with murder… until they go crazy, and mutually decide to commit suicide, after independently deciding to attempt to murder each other. Eek.
This guy doesn't mean much to anyone—except maybe his dad, Michaud. Olivier works at the police prefecture as the head clerk in the department of security. But he appears very little in the novel, and is usually observed through Thérèse's critical eyes.
Thérèse is described as disliking this "stiff, cold young man who felt he was honouring the shop in the arcade by bringing along the dryness of his lanky body and the weakness of his poor little wife" (4.3). Not exactly a flattering first impression.
Notably, in Chapter 10, Olivier shares the same opinion as his father: the police aren't always able to catch every single murderer. But if this book teaches us anything, it's that our own crimes—as well as, perhaps, our biology and our difficult life circumstances—inevitably catch up with us all.
Unlike the super-internally-sassy Thérèse, Suzanne is always described as meek. As with Suzanne's husband, Olivier, Thérèse has got nothing nice to say about Suzanne. She is described as "quite pale, with dull eyes, white lips and a soft face" (4.7).
But after Camille's death, Thérèse begins to suffer from hallucinations. So Suzanne becomes a welcome comfort to her, providing a steady companionship that Thérèse finds reassuring.
It's really all about Thérèse in this novel, isn't it? Too bad Madame Raquin thought it was all about her. So many egos, so little time.
This arrogant, clueless boaster is like the class clown of Thérèse Raquin. Grivet basically seems to be around in order to serve as the butt end of Zola's jokes. The most illustrative example of his complete cluelessness is the pivotal scene in Chapter 27 when Mme Raquin is trying to denounce the murderers.
As we know, Mme Raquin is unable to finish writing out her message. So Grivet claims that he has a perfect understanding of what Mme Raquin wants to say. He completes her sentence, but he has, of course, gotten it completely wrong.
This scene is one of most tragically ironic moments in the novel. And Grivet is instrumental in showing the dangers of miscommunication. Which we know all about, because sometimes it can be really hard to communicate over the interwebz. Are we right, Shmoopers?