Marcel Caux, born Harold Katte (1899 - August 22, 2004) was an Australian First World War veteran and the last known survivor of the Battle of Pozières.

Lying about his age, he enlisted on 6 September 1915, aged 16, and on 20 January 1916 embarked for France aboard HMAT Runic with the 9th Reinforcements of the 17th Battalion, Australian 2nd Division. He was transferred to the 20th Battalion with which he fought in the Battle of the Somme. He was wounded in the left ankle during the Battle of Pozières in 1916. He was wounded twice more, eventually being hurt so badly in 1918 that he was unable to bend his left leg for the rest of his life. He returned to Australia on 16 March 1919.

After the war he was refused an invalid pension , because the physician insisted that if he could stand up, he did not need one. Disillusioned with the army over this experience, he tore up all of his army photographs, moved into the Australian Bush and became a carpenter. He claimed for the next 80 years that he had been wounded in World War II, refusing to acknowlege his service during World War I. He married Doris and they had one son named Marcus, but never told them about his past.

His secret was discovered in 1998 when he was awarded the Légion d'Honneur by the French government. After this he was able to come to terms with his past and began attending Anzac Day ceremonies.

The centenarian Caux spent his final days in a nursing home in Chatswood, a suburb of Sydney. He remained opposed until he died to Australian involvement in foreign wars, in particular the 2003 invasion of Iraq. He died peacefully in his sleep.

Following Marcel Caux's death there were only four surviving Australian veterans of the First World War.