On 22 July 2014, Guingamp announced the loan of Marveaux on a season-long loan with an option to buy. Marveaux made his competitive debut as a 69th-minute substitute for Christophe Mandanne in the Trophée des Champions on 2 August, which his team lost 0–2 against Paris Saint-Germain at the Workers Stadium in Beijing. He scored his first goals in a 2–0 Europa League victory over PAOK on 2 October, netting in the 47th and 50th minutes.