Adhemar Decq was choirmaster of Saint-Honoré d'Eylau and was a student and graduate in Niedermeyer school, where some months after his graduation, was nominated Harmony teacher. He was organist of Saint-Jacques de Lisieux, then Levallois-Perret until 1889. Worked as professor in Paris, gave organ concerts for the Exhibition of 1889, with César Franck, Alex. Guilmant, E. Gigout, Ch.-M. Widor and Stolz. In this same year he obtained the post of Kapellmeister of Sain-Honoré d'Eylau.
He wrote music of all kinds: works for piano, harmonium, great organ, violin, etc ...; choirs at 3 and 4 voices, a cantata, a march for orchestra, pieces of military music performed by the Republican Guard, etc ... And member of the jury for the organ at the Conservatoire.