 Born in Feurs, Loire, Montagny started racing karts there in 1988, winning the cadet class in the French Karting Championship in 1992, and the National 1 class the following year.He made his debut in cars in 1994, aged 16, promptly winning the French Renault Campus championship.The next two years were spent in Formula Renault, with finishes in fourth (the highest-finishing rookie that year) and sixth (despite missing half the season with multiple fractures obtained in an accident at Le Mans) respectively, before transferring up to French Formula Three in 1997 with the La Filière Martini team, debuting with another fourth place championship finish.