First responsible for European affairs in the Brittany region between 1992 and 2000, Maillart then worked at the Caisse des dépôts et consignations.

[2] A member of the centrist Alliance, a component of the UDI, since 2014, Maillart-Méhaignerie was invested by the party on June 28, 2016, for the legislative elections of 2017 in the second constituency of Ille-et-Vilaine.

His investiture was not renewed following the agreement signed between the Republicans and the UDI for the legislative elections, probably because of her rallying to En marche!

On 18 June 2017, she won the second round of the legislative election by beating Les Républicains candidate Bertrand Plouvier, by 74.44% of the votes cast.

[5] In July 2019, Maillart-Méhaignerie voted in favour of the French ratification of the European Union’s Comprehensive Economic and Trade Agreement (CETA) with Canada.