At the age of nine, Curtil's mother (an artistic agent) encouraged him to enter Cours Simon, a theatrical training program in Paris for children.

At that time, he wanted to be a singer, then an impressionist, but his mother, knowing that show business was a difficult field but also certain of her son's potential, steered him toward acting.

This caught the attention of director Robert Hossein, who cast Curtil as Gavroche in an adaptation of Les Misérables, which aired as a miniseries on French TV in 1982.

However, that type of production is very tricky because economic constraints require shooting two episodes a day, and do not allow rehearsals; the actors must therefore spit out lines learned by heart the night before.

Curtil dubbed Mark-Paul Gosselaar in Saved by the Bell, then Dean Cain in Lois and Clark, Kyle Chandler in Early Edition, Doug Savant in Melrose Place, and above all Matthew Perry in Friends.