The attacker announced his retirement in front of 50,000 fans at his former club Cologne.
The 39-year-old was most recently playing for Gornik Zabrze in Poland, but came back to his boyhood team for one more match.
He said: "It's over on the pitch now, but we'll definitely see each other again off the pitch - whether in the stands or on the road.
"Once a Cologne fan, always a Cologne fan."
He added: "It really touches me that so many fans would like to come to enjoy this special evening with me.
"It is an honour for me to wear the Billygoat on my chest once more in front of a full house.
"It's a final declaration of love for this special city, the club with its fantastic fans, my team-mates for so many years and other people who have accompanied my path."