[3] As a rare example of a successful MoDem politician in Mayenne, Bannier was placed sixth in a Republican-Democratic and Independent-MoDem list led by Yannick Favennec in the department for the 2015 French regional elections in Pays de la Loire.
[4] During the 2017 French legislative elections, Bannier was the candidate of the electoral alliance between MoDem and La République En Marche (LREM) in Mayenne's 2nd constituency.
[6][7] Due to the law on the accumulation of electoral mandates, Bannier resigned from the office of mayor of Courbeveille on 1 September 2017.
[10][11][12] In 2018, Bannier became the vice-president of the parliamentary commission investigating the Lactalis affair, where the eponymous company's baby formula was found to be contaminated with Salmonella.
[20] Bannier was ultimately re-elected to the National Assembly with nearly 59% of the vote in the second round against the New Ecological and Social People's Union's Grégory Boisseau, who received 41%.