Vesper's feelings for Bond warm during the movie, but they take a giant jump after the torture scene. Verdict: Mathis has to be guilty of something. If Mathis wasn't working for Le Chiffre, there is no groundwork laid by Vesper + Le Chiffre to make Bond thing Mathis is a double agent, as Bond only puts Le Chiffre knowing his tell and the text message together as it happens. How is Mathis not a double agent? It is clearly said by Le Chiffre that Mathis works for him. I'm not going to drag this out, so here's my questions. I don't know if this reddit requires spoilers, or if an old movie does, but whatever.
