Poitrenaud made his debut for France during 2001, and was part of the French side which defeated the Springboks 20 to 10 in Paris. He earned a further two international caps for France that year, playing in the subsequent victories over Australia in Marseille and Fiji in Saint-Étienne. Toulouse made it to the final of the 2002-03 Heineken Cup, and defeated USA Perpignan to win the cup. Toulouse were also finalists of the domesttic competition, but were defeated by Stade Français.
He played in the 24 to 21 win over England in Paris. France would eventually win the 2004 Six Nations Championship. Toulouse made it to the final of the 2003-04 Heineken Cup, but were defeated by the London Wasps in the final. The scores were tied going into the last minute when Wasps player Robert Howley kicked the ball to the corner; Poitrenaud stood over the ball waiting for it to bounce into touch but it stayed in play and Howley chased the ball down and touched it down for the winning try .
Poitrenaud played another four times for France later that year; playing in matches against the United States, Canada, Argentina and the All Blacks. Toulouse were finalists of the 2004-05 Heineken Cup, and met fellow French club Stade Français (who defeated Toulouse in the domestic final of 2003). Stade Toulousain won the match 18 points to 12. He did not play any tests during 2005, or during the 2006 Six Nations Championship, but played in the wins over Romania and the Springboks in June 2006.
Poitrenaud sustained a broken ankle during a match between Toulouse and Perpignan on Saturday 16 February. He is expected to be sidelined for at least three months with this injury and as a result will miss out on France's remaining matches in the Six Nations championship. This came only a few days after he was recalled to the French national team by Marc Lievremont. The general manager of Toulouse Guy Noves has made some controversial statements regarding Clement's injury, he has commented that, ""Clement's injury is not down to bad luck but because the players are becoming exhausted," "Even if he didn't play in the Six Nations matches he still played the two championship games that took place at the same time.".