Mamzelle Dupont is a lively French mistress who is plump and has beady eyes. The french mistress is quite vunerable and has many jokes played on her by Alicia Johns and Betty Hill of Darrell Rivers form, June Johns (Alicia's cousin) and Freddie Holmes of Felicity Rivers form and Daffy Hope (Sally Hope's sister) of the First Form when Felicity is in the Sixth Form. Thankfully, Mamzelle Dupont has a good sense of humour and usually forgives the girls for their tricks. However, when Mamzelle has a difficult class or day she can have a short temper and can get quite angry with the girls sometimes resulting with harsher punishments than needed. Mamzelle plays her own "treek" where she wears fake teeth.

Mamzelle's relationship with the other French mistress Mamzelle Rougier much to the delight of the mistresses and teachers alike. Sometimes the two are best friends, rivals or bitter enemies. Mamzelle Rougier and Mamzelle Dupont had a big fight when Darrell was in the second form over Belinda Morris' portryal of the two fighting over the lead characters in the French plays.

Miss Potts the fiery head of North Tower shares an office with Mamzelle Dupont and is brought to despair with Mamzelle's queer ways.