FIFA has written to Matthias Blume, 31, after he found the tags while cleaning up the venue used to host the draw earlier this month.
He put them on eBay and quickly attracted bids in excess of $1,000.
A FIFA spokesman said: “FIFA has sent a warning to the legal representatives of the person concerned and pointed out that this is a violation of FIFA's name rights and that the auction should be stopped.
“If that doesn't happen, we will have to look at further legal steps.”
Blume, however, seemed set for a legal battle. He told reporters: “I want to see it through. I like a fight.”
