A by-election was held in the fifth constituency for French residents overseas on 8 April 2018, with a second round on 22 April as no candidate secured a majority of votes in the first round. The by-election was called after the Constitutional Council invalidated the election of Samantha Cazebonne, candidate of La République En Marche! in the June 2017 legislative elections, on 2 February 2018. Cazebonne was re-elected in the second round on 22 April 2018, albeit with a reduced margin compared to June 2017.