In 1945 (after the Second World War), she took over from Jacques Pignon (who died prematurely) the task of preparing, for the CNRS, a linguistic atlas of the center-west of France, focussing on the departments of Vendée, Deux-Sèvres, Vienne, Charente and Charente-Maritime: the Poitevin-Saintongeais dialect area.
At the time of her death, she had practically finished the surveys, which would be published by Brigitte Horiot under the title, Linguistic and Ethnographic Atlas: Poitou, Aunis, Saintonge, Angoumois.
His research was published in a work entitled, In Canada, the Upper Valley of Saint-Jean (Madawaska) and the future of Franco-American.
[2] In 1946, Massignon obtained a scholarship from the French Ministry of Foreign Affairs' Cultural Relations department which enabled her to travel to the Canadian maritime provinces and to the Mississippi delta region to collect traditional Acadian folklore and stories and survey the local dialects.
Besides her linguistic work, Massignon collected traditional stories and music from communities in Acadia, Brittany, Corsica and the west of France.