In a statement on their website, Cologne said: “The 29-year-old will continue his career in the Chinese Super League with Tianjin Quanjian.
“All relevant parties have reached an agreement. 1. FC Köln would like to thank Tony for his performances in the FC jersey whilst wishing him all the best for the future.”
German daily Bild reported that Modeste had moved to the Chinese side on a two-year loan deal for six million euros ($6.8 million) and that Tianjin Quanjian have an option to buy the Frenchman outright for 29 million euros.
Previous reports had said Modeste was the subject of a 35 million-euro bid, but Cologne had insisted last month that the player would be staying in Germany.
The 29-year-old scored 25 league goals last season, finishing behind only Bayern Munich’s Robert Lewandowski (30 goals) and Borussia Dortmund forward Pierre-Emerick Aubameyang (31 goals) in the Bundesliga scoring charts.
Modeste’s goals helped Cologne finish fifth in the German top flight and qualify for the group stage of the Europa League.