Eva Coupeau(pronounced as Eh-va) was the girl who saved Chuck Bass when he was shot in Prague at the end of Season 3 trying to protect his engagement ring for Blair. Eva is Chuck Bass's girlfriend at the beginning of Season 4. She is portrayed by Clémence Poésy.
She is first introduced when Chuck was mugged and washed up into her alley. Rescuing him and healing his wounds, she brings him to Paris where he tells her his name is Henry Prince. He lies because he's tired of being manipulative Chuck Bass.
Meanwhile, Lily is searching for Chuck back in New York, where he's been MIA for practically the whole summer. In Double Identity, she recieves a call telling her that a body with Chuck's ID and passport was found, and she sends Serena to identify the body.
While Serena goes to the morgue in Paris, Blair runs into Chuck on the street but they pretend not to recognize each other.
Eva was Chuck's first official girlfriend after Blair broke up with him in the finale of Season 3.
After much persuading, Chuck decides to go home to the Upper East Side, taking Eva with him.
Eva influences Chuck to become a new man: no more prostitutes, no more drugs. Chuck introduces her to his family at Fashion's Night Out. Lily has forgiven Chuck already, but Rufus is still angry at him for taking Jenny's virginity. Eric reveals what happened in Pilot between Chuck and Jenny, infuriating Rufus further.
Eva is nervous about meeting the Humphreys, worrying she wouldn't fit in with the high-class New York family. Later, she runs into Blair at a boutique where jealous Blair makes her feel even worse. At Fashion's Night Out, Eva overhears Chuck and Rufus's argument and leaves when Chuck denies her as his new girlfriend.
Chuck chases after her, revealing he is ashamed of himself and his behavior in the past. They kiss and make up (duh!) while Blair watches from afar.
Chuck gives Eva an expensive watch, and Blair becomes instantly jealous of their relationship. Blair visits the store where Chuck bought the watch, and sees Eva returning the watch. Blair shows the video she took of it to Chuck.
Eva explained to them, when confronted, that she used the money to help Chucks valet, Ivan, so he wouldn't be kicked out of his own home. Feeling guilty for accusing her, Chuck decides to donate five million dollars to a charity of Eva's choosing.
Blair spends time with Eva, trying to uncover her secrets show she can take her down, Waldorf-stlyle. Eva reveals that she grew up on a goat farm, with her cheese-making family. Eva dropped out of nursing school to help her family. Eva says she heard a gunfire one night outside of her apartment in Prague, and rushed to find out what it was.She said she had no idea that the man who lay before her was a billionare. She decided to nurse Chuck back to health.
Later in the episode, Dan, Serena and Blair discover that Eva was a prostitute.Chuck confronts Eva about it, and they reconcile, Chuck pretending to have known all along.
Unable to find an opportunity to return Chuck's personal belongings that were found when he was shot, she gives them to Ivan. Blair informs Chuck that Eva is a gold-digger, knowing who Chuck was before they met and taking his passport. Suspicious, Chuck looks through Eva's suitcase and lo and behold, finds his passport. When he sees Eva, he tells her to leave.
Later, Lily asks if he's gotten his belongings safely yet. She lists the things that were in the envelope, including his passport. Distraught, Chuck realized that Blair must have taken his passport from the envelope, put it in Eva's suitcase and made up the story about Eva knowing Chuck's identity. Chuck pursues Eva, trying to apologize and beg for her to stay, but the damage was done. Chuck had believed Blair over Eva when Blair had been trying to break them up from the beginning. Eva leaves New York and returns to Paris. She is not seen again in the show.