Léonie Duquet (April 9, 1916, Longemaison, Doubs, France – 1977, Argentina) was a French nun who was arrested in December 1977 in Buenos Aires, Argentina, and "disappeared". She was believed killed by the military regime of Argentine President Jorge Rafael Videla during the Dirty War. Alice Domon, a French nun working with Duquet, disappeared a few days later. They had been working in poor neighborhoods of Buenos Aires in the 1970s and supported the Mothers of the Plaza de Mayo, founded in 1977. Despite repeated efforts by France to trace the sisters, the Argentine military dictatorship was unresponsive.In 1990 a French court in Paris tried Argentine Captain Alfredo Astiz, known to have arrested Duquet and believed implicated in the "disappearance" of Domon, for kidnapping the two sisters.