Born in Paimpol, Côtes-d'Armor, Didot began his career playing for his hometown club Stade Paimpolais, before moving to Rennes in 1997. After successfully performing on the youth level, he was promoted to the senior squad during the winter break of the 2001–02 season and subsequently made his debut in a Coupe de France match against Le Havre. He made his league debut just four days later against Paris Saint-Germain coming on as a substitute in a 1–2 loss. Over the next two seasons, he was slowly integrated into the side appearing in 20 matches during the 2002–03 season and making 28 appearances during the 2003–04 season. The 2004–05 season was Didot's best season to date making 33 league appearances and also scoring his first league goal against RC Strasbourg in a 4–0 win. The club finished fourth in the league and qualified for the UEFA Cup, a first in the club's history.