The Chelsea defender started for Les Bleus in the Euro 2004 qualifier against Slovenia at the Stade de France, which the defending European champions won 5-0.
It was Gallas' first appearance for his country and the 25-year-old admits to feeling more than a little apprehensive as he entered the arena alongside club-mate and France captain Marcel Desailly, who was celebrating his 100th cap.
"When I came on to the pitch it was quite scary for me because it was the first time I was playing at the Stade de France," he said.
"My first touch of the ball was not good but I cheered up and my team-mates really helped me a lot, they talked to me and everything went all right. For me it was just the dream of a kid coming true.
"When I entered the stadium I experienced very high feelings. As a whole I've had a great impression about my first performance, we all played well, we were concentrated, it was just fantastic."