Mlle. Blache was originally prsented as an unpleasant but harmless individual, and was originally not falling into villainy, at least for the story's first half. However, in the later part, she fell into the unambiguous villainy for attempting to blackmail the culprit when she discovered their identity. She was killed soon afterwards.
She was portrayed by Miranda Raison in Agatha Christie's Poirot.
Ms. Blanche is the new French teacher of Meadowbank School for Girls. She was originally presented as a stern and unpleasant teacher with a dull method of teaching.
After the death of Ms. Springer, Mlle. Blanche discovered the culprit's true identity and decided to blackmail them. She met the culprit in the sport pavillion at one night, but she was ended up being killed.
Originally, the police suspected Mlle. Blanche to be the killer, but her death had erased any possibility of her being the culprit.
- Due to the self-serving reason behind her demise, Ms. Blanche became a great contrast to Julia Upjohn, the novel's deuteragonist. Julia managed to survive and became a pivotal role in the invesigation when she chose to ask for Poirot's assistance as soon as she discovered the jewels that the culprit was looking for. Unlike Ms. Blanche, Julia chose to assist Poirot when she had her chance, instead of exploiting the information for her own gain, thus ensuring Julia's survival.
- Miranda Raison, the actress of Mlle. Blanche in Agatha Christie's Poirot, later portrayed Sonia Armstrong in the 2017 film adaptation of Murder on the Orient Express.