[12] In late 2022, Maillard acted as interim leader of the Renaissance parliamentary group during Aurore Bergé’s maternity leave.

In July 2023, he announced his candidacy to succeed Bergé as the group’s chair[13] and was subsequently elected with 80 percent over the other candidate, Frédéric Descrozaille (20%).

[14] In July 2019, Maillard voted in favor of the French ratification of the European Union’s Comprehensive Economic and Trade Agreement (CETA) with Canada.

[15] On Maillard's initiative, a majority in the National Assembly agreed in December 2019 on a non-legally binding resolution modeled on the definition of antisemitism set by the International Holocaust Remembrance Alliance (IHRA).

[16][17] In 2021, Maillard filed a complaint for defamation against the newspaper Le Monde after it had linked him to a financial structure in the Seychelles as part of the Pandora Papers revelations.