NFL spokesman Brian McCarthy said the suit was filed Tuesday after Brown did not respond to requests that he pay back the money.
Brown returned to the NFL last season with the Ravens after being out of football since Dec. 19, 1999 when he was hit in the eye with a penalty flag weighted with metal pellets.
He filed a $200 million lawsuit and received $15-20 million from the NFL in a settlement on Oct. 9, 2002. According to The Washington Post, the settlement stipulated that if Brown returned to play, the NFL would get 50 percent of his after-tax income each season, up to a total of $1 million.
Brown played under a one-year $1 million contract last season for the Ravens.
The Ravens said Brown had no comment.
Information from The Associated Press was used in this report.