 On 3 January 2010, Jung signed a two-and-a-half-year deal.He made his AJ Auxerre debut against ES Wasquehal on 8 January 2011, coming on as substitute for the 62nd minutes in the 1–2 away defeat in the French Cup.On 29 January 2011, Jung made his Ligue 1 debut for AJ Auxerre, coming on as a substitute in the 85th minute in the 2–0 defeat by SM Caen.