There are 20 clubs in the league, with three promoted teams from Championnat National replacing the three teams that were relegated from Ligue 2 following the 2016–17 season.
All clubs that secured Ligue 2 status for the season were subject to approval by the DNCG before becoming eligible to participate.
Promoted from 2016–17 Championnat National Relegated from 2016–17 Ligue 1
Promoted to 2017–18 Ligue 1 Relegated to 2017–18 Championnat National
A promotion play-off competition was held at the end of the season, involving the 3rd, 4th and 5th-placed teams in 2017–18 Ligue 2, and the 18th-placed team in 2017–18 Ligue 1.