Deborah was discovered in 2005 by film producers Jean-Pierre and Luc Dardenne, who cast her in their gritty movie L'Enfant AKA The Child. The film won the the Palme d'Or at the 2005 Cannes Film Festival. The success of her debut convinced Deborah to leave school and launch a full-time acting career.
Her next movie, La Tourneuse De Pages AKA The Page Turner, happily saw her brave her first nude scenes. It brought her first César award. The second one came for her 2009 role in The First Day Of The Rest Of Your Life. In 2013, she was also nominated for the Magritte Award for Best Actress.