In the feature debut by Spanish director Estibaliz Urresola Solaguren, Otero plays a nine-year-old child who was born a boy but who considers herself a girl.

Collecting the prize, Otero fought back tears, later telling journalists that she was “very happy” to have won.

“I want to dedicate my life to acting,” she added.

Director Urresola Solaguren said it was important for her to pick a girl to play the role and not a boy.

“It is easier for her. She’s a really intelligent girl,” she said.

Germany’s Culture Minister Claudia Roth singled Otero out for a special congratulations for her “deeply moving portrayal of a trans child”.

The film “is a passionate plea against discrimination and for tolerance, openness and equality, especially through Sofia Otero’s interpretation,” she said.

Gender and identity issues were the focus of several films awarded at the festival on Saturday.

The prize for best supporting performance was awarded to Austrian transgender actress Thea Ehre for “Till the End of the Night”.

The movie, by German filmmaker Christoph Hochhaeusler, is a love story between a gay police officer and a transgender person against the backdrop of an investigation into a drug dealer.

Picking up the prize, Ehre had a special message for her parents.

“Thanks for supporting me, for always (giving) me the space to be what I wanted.”