The "Yes Man" star claims in legal papers filed Dec. 17 in Los Angeles Superior Court that Madden verbally offered her agent $2 million in August to endorse a line of shoes and accessories.
A few weeks later -- after some of Steve Madden's biggest retail customers balked at underwriting the costs of Deschanel as celebrity endorser -- the label talked her reps down to a $1.5 million fee, the documents claim.
The actress claims the reduced payment never materialized, even though Deschanel made appearances for the brand and turned down other endorsement deals in the interim.
The actress is seeking her fee plus a percentage of profits.
Madden's reps did not immediately return StyleList's calls seeking comment.
This is not the first time Madden has gotten into legal trouble in recent years. The brand was sued in 2009 for copyright infringement for allegedly producing a look-alike version of Balenciaga's signature "LEGO" heels. Madden himself served serious prison time after a 2002 conviction for securities fraud.
Then again, the shoe designer did come to the rescue of designer Betsey Johnson, bailing out her troubled company with a big loan.
Also, read about the noted fashion photographer who has sued Skechers.