A lawmaker with Macron's party, Amélie de Montchalin becomes junior minister for European affairs, a statement from the French presidency said Sunday.
Former European Affairs Minister Nathalie Loiseau left the government to lead Macron's party in European parliamentary elections in May.
Ndiaye, 39, and O, 36, respectively replace Benjamin Griveaux and Mounir Mahjoubi, both of whom resigned from the government last week to run for Paris mayor in 2020.
Their exits bring to 10 the number of ministers who have quit since Macron’s election to the presidency in 2017, a record at this stage of a presidential term.