The team made the move despite knowing Peppers' desire to play elsewhere next season.
Earlier this week, his agent, Carl Carey, gave Panthers' officials a list of four teams to which Peppers would accept a trade, with Dallas at the top.
"Julius was expecting the franchise tag and we will continue to seek a resolution that is in line with his professional goals," Carey said in a statement.
By franchising Peppers, the Panthers automatically are required to make him a one-year tender offer of $16.683 million, a 20 percent increase over his 2008 salary cap figure.
The 6-foot-7 inch, 283-pounder, a first-round pick by the Panthers out of North Carolina in the 2002 NFL draft, has totaled 70 ½ sacks among 278 tackles in seven seasons.