Born in 1963, Mariana Otero, after a Master's degree in Literature at Paris 8 and film studies at IDHEC, is passionate about documentary film.

She directed several films for Arte, including La loi du collège, which was to become the channel's first documentary series.

Between 1995 and 2000 she lived in Portugal where she directed Cette télévision est la vôtre. By revealing the functioning of the largest commercial television in the country, CLC, this film will create a huge controversy. Then she returned to France and turned to cinema, notably with Histoire d'un secret. This film, at the end of an investigation into a family secret, reveals a political and social taboo. It will be awarded in many international festivals.

In 2010, she directed In Our Hands, which tells the story of how employees discover a new freedom by trying to transform their company into a cooperative. This film will be nominated for a César for Best Documentary in 2011.

In 2013, she directed À ciel ouvert, a film that allows us to understand the singular vision of the world of psychically and socially disadvantaged children. In addition, she teaches at the Ateliers Varan, of which she has also been a member since 2000, at the Femis, at the University of Jussieu, Poitiers (Creadoc) etc...

She is a member of Acid, of which she was co-chair from 2010 to 2012.