Abel-Marie Decaux (11 February 1869 in Auffay – 19 March 1943 in Paris) was a French organist and composer. He studied organ with Charles-Marie Widor and Alexandre Guilmant, and composition with Jules Massenet. He served as organist at the Basilique du Sacré-Cœur, in Paris, for 25 years until 1923, when he went to the US to teach organ at the Eastman School of Music in Rochester, NY. He returned to France in 1935, to teach organ at the École César Franck and at the Institut Grégorien in Paris.Decaux's best-known composition (and the only one he ever published), Clairs de lune, is a set of four piano pieces written between 1900 and 1907, and published in 1913. It is remarkably modern for its time, anticipating both Claude Debussy and Arnold Schoenberg.