During this period, Asso also wrote songs for Marie Dubas including "Le Fanion de la Légion" ("The Legion's Flag") and "Mon légionnaire" ("My Legionnaire").
In August 1939, Asso was called up to the French army due to World War II and his collaborations with Piaf were brought to an end.
[2] After his service in the war Asso went on to write lyrics for other artists including Lucienne Delyle, Marcel Mouloudji and Renée Lebas.
The 1950s were a prolific period for the writer and he also found commercial success with songs such as "Y’a tant d’amour" (sung by Renée Lebas) and "Un petit coquelicot" which was written for Marcel Mouloudji.
Towards the end of his life Asso moved away from writing lyrics and between 1962 and 1968 he was administrator of the Société des auteurs, compositeurs et éditeurs de musique (SACEM).