In 2010 K League, he succeeded in scoring double-digit goals again in 7 years and led FC Seoul to champion of 2010 season.

After spearheading FC Seoul's run to the K League title, Jung agreed terms with French Ligue 1 outfit AJ Auxerre.

By accepting Auxerre's contract offer, he became the third Korean at the time to ply his trade in Ligue 1.

[1][2] 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.

[3] 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.