A by-election was held in Haute-Garonne's 8th constituency on 11 March 2018, with a second round on 18 March as no candidate secured a majority of votes in the first round. The by-election was prompted after the Constitutional Council invalidated the election of Joël Aviragnet, candidate of the Socialist Party (PS), in the June 2017 legislative elections on 18 December 2017.
Aviragnet was re-elected by a massive margin in the second round rematch against Montsarrat, securing over 70% of valid votes and winning by a margin 40 points larger than in June 2017.
Background
Following the second round of the 2017 legislative election in Haute-Garonne's 8th constituency on 18 June, Michel Montsarrat, candidate of La République En Marche! defeated by 91 votes, filed an appeal with the Constitutional Council appealing the election of Joël Aviragnet of the Socialist Party (PS). Montsarrat questioned a number of irregularities, including those in several communes where Aviragnet multiplied his result in the second round.
On 18 December, the constitutional council annulled the election of Aviragnet, considering the irregularities listed by Montserrat to have affected 4 votes given differences in signatures indicating that votes were not given by the voter in question, 1 vote in Saint-Bertrand-de-Comminges and 10 votes in Montastruc-de-Salies given discrepancies between the number of ballots and signatures, and 64 votes in the only polling station in Gensac-de-Boulogne where article L. 68 of the electoral code, requiring the registration lists of every polling station and associated documents be transmitted along with the record of voting operations after the completion of voting, was not respected. Given these issues, and the small number of votes separating the two candidates, the constitutional council judged it appropriate to annul the result and call a by-election within the constituency. The first and second rounds of the by-election are scheduled for 11 and 18 March 2018, with candidacies to submitted between 12 and 16 February.
Polling stations throughout the constituency will be open from 8:00 to 18:00 CET, with those in Saint-Gaudens open until 19:00 CET.
Candidates and campaign
Michel Montsarrat, a former rugby player for AS Béziers Hérault, later a restaurateur, and hotel manager living in Luchon, was once again invested as a candidate of La République En Marche!, supported by the nine deputies of the presidential party in the department. On 30 January, the Union of Democrats and Independents (UDI) decided to back Montsarrat in the by-election, breaking from the party's historical alliance with the right. The initial campaign of Montsarrat was considered lethargic, and was perturbed by the apparent theft of the laptop of his campaign director on 25 January, adding to existing frustration with his campaign management. Montsarrat was castigated early on over the potential closure of the court of Saint-Gaudens, and later over the invitation of Montsarrat to a visit by Laura Flessel as a "deputy for Haute-Garonne" on a published list of invitees. On 9 January, justice minister Nicole Belloubet visited the constituency in support of Montsarrat, the first of a series of ministers to visit the constituency to campaign, followed by Minister of Territorial Cohesion Jacques Mézard on 12 February, government spokesman Benjamin Griveaux on 15 February, and finally Christophe Castaner on 2 March. Castaner held a second public meeting, this time alongside Genevieve Darrieussecq, on 3 March, and Jean-Michel Blanquer and Gérard Collomb traveled to the constituency on 9 March. Local elected supporters, including deputy Mickaël Nogal and mayor of Rieumes Jennifer Courtois-Périssé, attended a public meeting with Montsarrat on 23 February.