Alimen's career was mainly focused on Quaternary geology in France and Africa while working for Centre national de la recherche scientifique (French National Centre for Scientific Research, or CNRS).
[1] (one of the first women to submit a submit a thesis for a PhD in the field of prehistory),[2] her thesis was titled Étude sur le Stampien du Bassin de Paris (A Study of Stampien from the Paris Basin).
In 1948 Ailmen went to work for Centre national de la recherche scientifique, studying the Quaternary geology of the Pyrenees and the Sahara.
[3] She later managed the Laboritoire du Géologie Quaterniare for CNRS[2] in Paris, which continued to study Quaternary geology in the two regions.
Alimen also served as President of the Société Préhistorique Française (Prehistorical Society of France) in 1946 and again in 1960.