On 15 April, Paris Saint-Germain won their seventh Ligue 1 title with five games to spare following a 7–1 victory over Monaco.
[6] Twenty teams competed in the league, with three promoted teams from Ligue 2: Strasbourg (Ligue 2 champions, after a nine-year absence), Amiens (Ligue 2 runner-up, their first ever Ligue 1) and Troyes (winner of the relegation play-off against Lorient, with immediate return), replacing the three relegated teams from the 2016–17 Ligue 1 season: Bastia (finished 20th, after five years), Nancy (finished 19th, with immediate return) and Lorient (lost the relegation play-off against Troyes, after 11 years).
The 2017–18 season ended with a relegation play-off between the 18th-placed Ligue 1 team, Toulouse, and the winner of the semifinal of the Ligue 2 play-off, Ajaccio, on a two-legged confrontation.
The first match, which was supposed to be held in Ajaccio, took place behind closed doors in Montpellier.
[26] Toulouse won 4–0 on aggregate and therefore both clubs remained in their respective leagues.