Legislative elections were held in France on 11 and 18 June 2017 (with different dates for voters overseas) to elect the 577 members of the 15th National Assembly of the Fifth Republic. They followed the two-round presidential election won by Emmanuel Macron. The centrist party he founded in 2016, La République En Marche! (LREM), led an alliance with the centrist Democratic Movement (MoDem); together, the two parties won 350 of the 577 seats—a substantial majority—in the National Assembly, including an outright majority of 308 seats for LREM. The Socialist Party (PS) was reduced to 30 seats and the Republicans (LR) reduced to 112 seats, and both parties' allies also suffered from a marked drop in support; these were the lowest-ever scores for the centre-left and centre-right in the legislative elections. The movement founded by Jean-Luc Mélenchon, la France Insoumise (FI), secured 17 seats, enough for a group in the National Assembly. Among other major parties, the French Communist Party (PCF) secured ten and the National Front (FN) obtained eight seats. Both rounds of the legislative election were marked by record low turnout. 
In total, 206 MPs lost reelection, and 424 (75%) elected MPs were new members. There was a record number of women elected. The average age of parliamentarians decreased from 54 to 48. Ludovic Pajot from the National Rally became the new Baby of the House, being elected at the age of 23. Édouard Philippe, appointed as Prime Minister by Macron following his victory in the presidential election, was reappointed following the second round of the legislative elections and presented his second government by 21 June. The 15th legislature of the French Fifth Republic commenced on 27 June.
Background.
In France, legislative elections take place about a month after the second round of the presidential election, held on 7 May. Prior to 2002, the presidential and legislative elections were not always held in the same year; following the victory of the UMP in the 2002 legislative elections, the two were synchronized to minimize the risk of cohabitation.
In the first round of the presidential election, on 23 April, Emmanuel Macron of En Marche! and Marine Le Pen of the National Front (FN) advanced to the runoff after placing first and second, respectively, and were followed closely by François Fillon of the Republicans (LR) and Jean-Luc Mélenchon of la France Insoumise (FI). In the first round, Macron led in 240 constituencies, against 216 for Le Pen, 67 for Mélenchon, and 54 for Fillon.
Macron won the second round on 7 May against Le Pen, securing 66.1% of valid votes.
Upon the close of nominations for the legislative election, the Ministry of the Interior published a final list on 23 May containing a total of 7,882 candidates, with an average of 14 candidates within each constituency.
The 2017 legislative election was the first held after the legal abolition of the dual mandate in France in 2014; deputies will no longer be allowed to concurrently serve in local government, frequently as mayors, upon election to the National Assembly.
Electoral system.
The 577 members of the National Assembly are elected using a two-round system with single-member constituencies. Candidates for the legislative elections had five days, from Monday 15 May to 18:00 on Friday 19 May, to declare and register their candidacy. The official campaign ran from 22 May to 10 June at midnight, while the campaign for the second round runs from 12 June at midnight to 17 June at midnight, with eligible candidates required to declare their presence by 18:00 CEST on 13 June. 
To be elected in the first round, a candidate was required to secure an absolute majority of votes cast, and also to secure votes equal to at least 25% of eligible voters in their constituency. Should none of the candidates satisfy these conditions, a second round of voting ensues. Only first-round candidates with the support of at least 12.5% of "eligible" voters are allowed to participate, but if only 1 candidate meets that standard the two candidates with the highest number of votes in the first round may continue to the second round. In the 2017 election, four deputies were elected in the first round. In the second round, the candidate with a plurality is elected. Of the 577 constituencies, 539 are in metropolitan France, 27 are in overseas departments and territories and 11 are for French citizens living abroad.
Voting in the first round took place from 08:00 to 18:00 (local time) on Saturday 3 June in French Polynesia and at French diplomatic missions in the Americas, and on Sunday 4 June at French diplomatic missions outside the Americas. Voting in the French overseas departments and territories in the Americas (i.e. French Guiana, Guadeloupe, Martinique, Saint Barthélemy, Saint Martin, and Saint Pierre and Miquelon) took place from 08:00 to 18:00 (local time) on Saturday 10 June. Voting in metropolitan France (as well as the French overseas departments and territories of Mayotte, New Caledonia, Réunion and Wallis and Futuna) took place from 08:00 to 18:00 or 20:00 (local time) on Sunday 11 June.
Voting in the second round took place on Saturday 17 June from 08:00 to 18:00 (local time) in the French overseas departments and territories situated east of the International Date Line and west of metropolitan France (i.e. French Guiana, French Polynesia, Guadeloupe, Martinique, Saint Barthélemy, Saint Martin and Saint Pierre and Miquelon), as well as at French diplomatic missions in the Americas. Voting in metropolitan France (as well as the French overseas departments and territories of Mayotte, New Caledonia, Réunion and Wallis and Futuna, and French diplomatic missions outside the Americas) takes place from 08:00 to 18:00 or 20:00 (local time) on Sunday 18 June.
The 15th National Assembly convened on 27 June at 15:00 CEST.
Campaign.
La République En Marche! and MoDem.
En Marche!, the movement founded by Emmanuel Macron, who won the presidential election under its banner, planned to run candidates in all 577 constituencies under the banner of "La République En Marche!", of which at least half were planned to be from civil society – the other half having previously held political office – and half women. No "double investiture" was permitted, though the original requirement of prospective candidates to leave their previous political party was waived by Macron on 5 May. In addition to those parameters, he specified in his initial press conference on 19 January that he would require that candidates demonstrate "probity" (disqualifying any prospective candidates with a criminal record), "political plurality" (representing the threads of the movement), and "efficacy". Those wishing to seek the investiture of En Marche! were required to sign up online, and the movement received nearly 15,000 applications by late April. For nominations sought by those in the political world, the popularity, establishment, and ability to appear in the media of applicants are also considered, with the most difficult cases adjudicated by Macron himself. To represent themselves under the label of La République En Marche!, however, outgoing deputies must decide to leave the Socialist Party (PS) or the Republicans (LR).
After his victory in the presidential election, Macron resigned his post as president of En Marche!, with Catherine Barbaroux appointed as interim president. The movement, renamed, presented candidates under the label of "La République En Marche!"; though the full list of 577 investitures was to be published on 11 May, Jean-Paul Delevoye, president of the investiture commission, later indicated that the total published that day would be "about 450". The delay was attributed to an influx of applications following Macron's victory in the presidential election – more than a thousand, bringing the total to over 16,000 – with additional complexity arising from the interest of former Prime Minister Manuel Valls in standing as a La République En Marche! candidate without either submitting an application or leaving the Socialist Party. Since the announcement that "La République En Marche!" would be transformed into a formal political party, however, the conditions of securing an investiture tightened considerably, with candidates expected to be "administratively" attached to the party to prevent public funding (distributed on the basis of electoral results) from being received by the PS or the Republicans.
The initial list of 428 investitures was revealed on 11 May, with exact gender parity (214 men and 214 women), with 94% of candidates not outgoing deputies; 93% employed, 2% looking for work, 4% retired, 1% students; 52% from civil society; an average age of 46 (the youngest being 24 and oldest being 62), compared to 60 for outgoing deputies; and 24 current deputies, mostly Socialists, invested under the label of La République En Marche! The total number of remaining investitures to be concluded is 148. No candidate was invested against Valls. Numerous candidates were invested in error, including Mourad Boudjellal, François Pupponi, and Augustin Augier, who did not apply; Stéphane Saint-André, an outgoing PRG deputy who renounced his investiture and raised concerns about the potential appointment of Édouard Philippe as prime minister; and Thierry Robert, an outgoing deputy who contravened the requirement of not having a criminal history.
The list was further updated on 15 May with an additional 83 candidates, of which half were proposed by the MoDem, bringing the overall total to 511, and leaving 66 constituencies to be decided, of which about 30 are reserved for figures on the right and left who expressed support for Macron's project and most of the rest constituencies for overseas departments; ultimately, 51 constituencies with outgoing deputies on both the left and right considered "Macron-compatible" were not contested; Delevoye stated that some twenty constituencies for overseas France were frozen due to local party financing peculiarities, with other vacated constituencies for other political personalities apparently interested in joining in the presidential majority.
On 15 May, Édouard Philippe, a deputy of the Republicans, was appointed as Prime Minister. After the selection of ministers to the newly formed government on 17 May, the movement announced that it would not invest candidates in 56 constituencies, hoping to protect a number of those on the left and right who had expressed support but not rallied, with the possibility of adjustments before the deadline on 19 May. Appointed ministers contesting the legislative elections were obligated to resign if not elected: namely, Christophe Castaner, Marielle de Sarnez, Richard Ferrand, Annick Girardin, Bruno Le Maire, and Mounir Mahjoubi; all six were eventually elected.
MoDem.
After François Bayrou endorsed Macron in February, the Democratic Movement (MoDem), which he leads, was reportedly to receive 90 constituencies, of which 50 were considered winnable, for its candidates. However, hours of the publication of the initial list, Bayrou indicated that it did not have the "approval" of the MoDem, unsatisfied with the number of constituencies for MoDem candidates, and appealed to Macron to permit joint investitures and planned to convene the political bureau of his party on 12 May. He was also unhappy with what he called a "recycling operation of the PS"; according to a tally by MoDem officials, among the 428 investitures announced, 153 were granted to PS/ex-PS/PRG, 38 to the MoDem, 25 to LR or miscellaneous right, 15 to UDI/ex-UDI, and 197 to civil society figures. On 12 May, Bayrou announced that he had secured a "solid and balanced" draft agreement, claiming that his party would ultimately obtain a bit more than a hundred investitures. A MoDem candidate replaced Gaspard Gantzer, former communications advisor to Hollande, in Ille-et-Vilaine's 2nd constituency after fierce objections by local activists and his renunciation of the investiture, which he claimed he did not apply for, and mayor of Mont-de-Marsan Geneviève Darrieussecq and Senator Leila Aïchi, both members of the MoDem executive bureau, received investitures.
Bayrou's party hopes to elect at least 15 deputies, necessary for the formation of a parliamentary group in the National Assembly; additionally, to be reimbursed for expenses, the party must receive at least 1% of the vote in at least 50 constituencies where it is present. Public financing is also allocated as a function of the number of elected officials, hence the ambitions of the MoDem.
The Republicans (LR) and UDI.
On 2 May, François Baroin was appointed by the political bureau of the Republicans (LR) to head the campaign for the legislative elections. A week before, he said that he would be available to serve as Prime Minister in a cohabitation government under Emmanuel Macron and considered it impossible not to run on the same program as its defeated presidential candidate François