Marty was first called up to the French rugby team during the 2005 Six Nations Championship, making his first appearance as an unused bench replacement in the match against Ireland at Lansdowne Road. He was elevated to the starting line-up for the subsequent match against Italy, and scored two tries in the match at Stadio Flaminio in Rome, which France won comfortably 56–13. Marty was capped in a Test against Canada in November in which he scored a try as well. He was also capped in the following match against Tonga.
Marty was included in France's 2006 Six Nations Championship squad, and was included in the starting line-up in the match against Ireland at Stade de France in Paris and scored two tries in the 43–31 victory. He was a used bench replacement in the match against Italy as well. France went on to win the tournament. He was capped again in a mid-year test against Romania also.