Suzanne Hertz, known by the students as Mrs. Hertz or Ms. Hertz and by Jim as Suzanne, is the science and homeroom teacher at Kadic. She also replaces Franz Hopper as a science teacher. She usually does a lot of experiments with her students, most of which either help them or infect them with a X.A.N.A. virus. She also cracks a few jokes, which causes her and her students to laugh. She also does not seem to care if students just jump out of class, as seen with Yumi in Killer Music. She was the target of X.A.N.A.'s scheme once, in Zero Gravity Zone. She is the crush of Jim Morales, the PE teacher and campus supervisor, in the second season. However, she may be having feelings for him, too, despite her implied marriage. She seems to think that Jeremie and Herb are two of her best students and Ulrich and Odd as two of her worst. Suzanne is also one of Mr. Delmas's personal advisors, the other being Jim. Jim is strongly attracted to her, but it's unknown canonically how her feelings are toward him. She likes to dance and can be rather strict at some times, but is rather kind in times of danger.
In regards to physical appearance and voice, she usually looks and sounds like a woman in her 60s. In Code Lyoko her hair is grayish but in Code Lyoko Evolution her hair is brown.
In Satellite, it is revealed that she is also a member of the Administrative Staff. Jim and her are eating lunch together in the Cafeteria as well.
In New Order, she gave Sissi a zero for drawing an Amazonian yucca from the local florist's when she could've drawn something from the woods.
In Cold War, even though it wasn't shown, Mrs. Hertz took some of the children into the basement level of the Science Building.
It is revealed in Wrong Exposure that Mrs Hertz replaced Franz Hopper as the Kadic science teacher prior to Franz Hopper's disappearance.
It is revealed in Lyoko Minus One and The Lake that Suzanne loves nature; her favorite thing about Earth is forests, and she is especially concerned about the effects pollution would someday have on them and all life. In The Lake, she also gives a short but passionate speech about the island that she, Jim, and the children will be camping in for the weekend, calling it their "home" and "a true Garden of Eden". Because of her love of nature, a few fans have casually called her "the Queen of Green".
Sometimes, Suzanne is drawn without the crow's feet behind her eyes and the wrinkles beside her mouth, making her face look younger. In the beginning scene of Nobody in Particular, her usual "old lady" inflections in her voice disappeared too, but only for a sentence or two.
Though she claimed to be dating someone else, Jim has feelings for Suzanne; it has been shown that she, too, gets a bit flirty with him at times. Although Jim is attracted to her, she appears to have a relationship with an unseen character named Pédro. It can also be argued that she may just be lying about this relationship in order to get Jim jealous, and is probably waiting to tell him the truth. It's unknown if he still has feelings for her in Evolution.
Suzanne is a member of the Council of Representatives (along with Jim, Jean-Pierre, and Odd).
In the actual canon, Suzanne has a mixed attitude towards her students. As an example of her positive side, she is usually kind to them during emergencies and field trips. But, as an example of her despotic side, there are examples of the children causing her a lot of stress, an example being in Code Lyoko: Quest for Infinity when she states that she is having nightmares because of her students.
In The Lake, Odd saves Suzanne from being crushed to death by a falling tree.
In Nobody in Particular, it was shown that she doesn't know how to ballroom dance, and needed lessons. Specifically, she needed Argentine Tango.