Ivanka Trump Visits 'FOX & Friends' Ilya S. Savenok/Getty Images A San Francisco retailer is suing Ivanka Trump's fashion brand for using Donald Trump's presidency to create an "unfair advantage."

On Thursday, Modern Appealing Clothing (MAC) filed a class action lawsuit against the Ivanka Trump brand for "unlawful" and "unfair" promotional activities, Courtroom News Service reported.

"President Donald J. Trump and his individual and White House employees and agents have, since the election, promoted defendant Ivanka Trump brand by exploiting the power and prestige of the White House," the complaint reads, citing Trump's anti-Nordstrom tweet and Kellyanne Conway's advice that Americans "go buy Ivanka's stuff."

The complaint also argues that employees at Ivanka Trump exploited the first daughter's elevated position post-election, saying that the company "piggy-back[ed]" promotion of items on government events. While the lawsuit doesn't cite particular instances, a potential example would be the brand promoting a bracelet that Ivanka wore on "60 Minutes" in December.

The impact of Trump's election on Ivanka Trump's brand has been difficult to unpack.

The lawsuit says MAC's business has been negatively impacted because, since the election, sales of Ivanka's brand have surged several hundred percent compared to last year (a Slice Intelligence report says US sales of the brand on Amazon grew 332% in January and February compared to 2016). However, the brand has also been cut from a number of retailers in recent months, including Nordstrom, Neiman Marcus, and Gilt.

MAC is asking that California stops selling Ivanka's brand while it enjoys an allegedly unfair advantage. The lawsuit also demands that the brand pay "ill-gotten gains" since the election to MAC and other retailers included in the class action.

Representatives for Ivanka Trump's brand didn't immediately respond to request for comment.