The 17-year-old Columba College pupil said she only entered the annual Jeunes Auteurs pour L'Europe (Young Writers in Europe) competition as part of the school's Gifted and Talented Education programme, to extend her French literacy.
Ellen spent eight weeks writing a short story in French about a young woman who hit her head, and her ensuing memory loss and confusion.
To her great surprise, she won the year 12 category contested by secondary school pupils from New Zealand, Australia and Europe.
"I'm stunned. It was never really part of the agenda."
Ellen said her English parents taught her basic French vocabulary when she was young.
Later, she took classes at school.
Writing the essay was time-consuming: "It's the little things like tenses, French idioms and cultural expressions that take a lot of work."
She hopes to live in France, study and practise law.
"The culture, the castles and the people have always appealed to me. I've been motivated by what I've learnt about France at school."
