In 1915, Houénou was given French citizenship, an extremely rare status in colonial Africa for people of African descent at that point, with fewer than 100 being citizens of France by 1920. By 1918, he was admitted into the bar association and became a minor celebrity in Paris, with rumors of relationships (most notably with French actress Cécile Sorel) published in the French papers. Houénou became involved with the French intellectual scene and tried to be active as a public intellectual, including the 1921 publication of a scientific study of phonetics and linguistics titled L’involution des métamorphoses et des métempsychoses de l’Univers – L’involution phonétique ou méditations sur les métamorphoses et les métempsychoses du langage.
