She studied French and Spanish at Trinity College, Cambridge in the 1980s, where she became a member of the Footlights theatre group, writing and performing her own material.
In the 1980s she joined the Traverse Theatre in Edinburgh, appearing in the premiere productions of Losing Venice and The White Rose.
Duchêne is best known for her work as Miss Constance Hardbroom, the strict "deputy head and potions teacher" on the popular TV series The Worst Witch.
From October 1987 to July 1991, Duchêne played Alex Parker in BBC Radio 4's drama series Citizens.
Duchêne spent her infancy in France, and was brought back to England permanently in 1962, residing in the seaside town of Brighton.