Her older brother, Marcel de Souza, introduced her to her future husband, Thomas Boni Yayi.[1] She and Boni Yayi have five children. In 2008, Chantal Yayi and Thomas Boni Yayi, who is a descendant of the Yoruba princes of Sabe in his own right, were awarded chieftaincy titles by the Nigerian king of Ile-Ife, Olubuse II.[4]
As first lady, Yayi focused on education and healthcare.[5]
In preparation for the 2016 Beninese presidential election, Yayi helped her brother set up a small political party, the Republican Front for a Patriotic Alternative, or Front républicain pour une alternative patriotique, (Frap), which Marcel Alain de Souza chaired and used to launch his presidential candidacy.[5] However, Marcel de Souza received only 0.13% of the vote.[6]
In 2021, Yayi reportedly suffered a stroke following months of health problems.[7] She was initially treated in the intensive care unit of Centre National Hospitalier Universitaire-Hubert Maga (CNHU) in Cotonou before being flown to a hospital in Europe for additional treatment in early May 2021.[7]