Marconnet played in all of France's 1999 Five Nations Championship. He played in two June tests that year, in games against Tonga and Romania. Stade Français did make it to the final of the domestic championship, which they won, defeating US Colomiers. He did play in three tests in November 2000 though, in a match against Australia, and two against the All Blacks. In 2001 Stade Français were finalists at the 2000–01 Heineken Cup which was lost to the Leicester Tigers in the Parc des Princes, Paris, and he played in all of France's 2001 Six Nations Championship fixtures, and did the same the following season, in the 2002 Six Nations Championship, as well as getting another three caps for France in November of that year.