Perpignan made it to the final of the 2002-03 Heineken Cup, but went down to fellow French club Stade Toulousain. Mas made his international debut in a match against the All Blacks on 28 June 2003. He did not play at the 2003 Rugby World Cup in Australia later that year. Perpignan made it to the final of the Top 14 in 2004, but were defeated by Stade Français, 38 to 20. In the summer of 2013, Mas moved to ambitious fellow Top 14 club Montpellier Hérault Rugby.
International career
Mas made his debut for the France in 2003. He did not play for France in 2004, being an unused bench replacement in tests against Australia and Argentina in November. The following year he played four times for France during the 2005 Six Nations Championship.