Colette is a very tough, assertive woman who is very hardworking. She is very fierce and strong, as shown when she is forced to train Linguini, and immediately sticks knives in his sleeves as she tells him she won't let a new trainee screw up all of her hard work. During her training with Linguini, she scolds him for taking his time while cooking and later threatens to kill Linguini if he can't keep his station clean. Colette herself states that the reason she is the only woman in the kitchen where cooking is regulated "by rules of stupid old men who make it impossible for women to cook" is because she is the toughest cook in the kitchen.
However, despite some of her tougher qualities, she is a firm fan and believer in Gusteau and his famous motto: "Anyone can cook." She has also memorized all of his recipes by heart. Her strong belief in his words causes her to defend Linguini from being fired by Chef Skinner, saying that it would betray Gusteau's words especially after LeClaire said she liked the soup he made. Her belief in Gusteau's words is so strong that despite having initially thought Linguini was crazy to say that Remy (a rat) was the one revealed to be the cook, she goes back after remembering Gusteau's words and later works together with Remy (while the rest of the staff left after thinking Linguini was crazy) as a cook in Gusteau's and later in Remy and Linguini's bistro, La Ratatouille.
Colette is the only female cook in Chef Skinner's kitchen at Gusteau's. She is a capable cook, hard working and very tough to enter the masculine world of haute cuisine. She had defended Linguini from being fired as a garbage boy when Skinner caught him "cooking" the soup in which Remy had made. She takes Linguini under her wing and teaches him the skills necessary to survive in the fast-paced kitchen. She was at first unaware of Luigini's admiration for her. Colette felt disgruntled when Skinner took a personal interest into Linguini, which in fact Skinner was trying to force the truth of Linguini's cooking.
The next day, she tells a sleepwalking Linguini (puppeteered by Remy at the time) that she likes him, and storms out after mistaking his lack of reaction for snobbishness. Linguini awakens and struggles to tell her the truth. Colette is initially puzzled by his actions and raving behavior and slips a hand into her bag for a canister of mace. Remy desperately makes Linguini fall onto Colette to prevent him from talking further and the two kiss. Colette is equally surprised as Linguini but quickly falls in love, dropping the mace. A romantic relationship quickly blossoms after this incident.
When Linguini suddenly inherits the restaurant when Remy successfully steals papers and will that testify that Linguini is Gusteau's secret son, he and Colette run the restaurant.
Food critic Anton Ego arrives with a challenge for the restaurant, and Colette prepares only to discover that Linguini had no ability to cook. When Linguini defends Remy, Colette listens to his claim that the rat is the real cook. Tearfully, she believes that Linguini has lost it, and so leaves him. However, she remembers Gusteau's motto: "Anyone can cook" (a phrase she deeply believes in) and returns to aid Linguini and Remy in the cooking.
Ego is successfully dealt with, and he requests to see the chef. Reluctantly, she allows Remy to be unveiled as the true chef and Ego leaves, reformed. Later, Gusteau's was closed down due to rats in the kitchen, but Colette has found cooking at a new Parisian bistro, along with Linguini and Remy, with Ego as a patron and queues stretching around the block.
- Aside from being the only female chef in Gusteau's Restaurant, Colette is also the only main female character that appears in Ratatouille.
- In Your Friend the Rat, there is a scene where Remy is holding hands with a little girl that looks like her.
- Colette appears on a magazine cover in Inside Out when Riley pretends the floor is lava in her old home.