Amazon is facing legal action regarding its influence in the book world.

A class action lawsuit, filed on March 25 in federal court in New York, charges the online retail giant with colluding to fix prices on print books. Seattle law firm Hagens Berman alleges Amazon holds contracts with the five largest publishing houses that prohibit them from selling books to other retailers for less than what they charge Amazon.

Amazon did not respond to Fortune’s request for comment about the suit.

The legal action comes nine years after Apple and the five major publishers settled charges that they had colluded to raise the price of e-books, as they were unhappy with Amazon’s e-book price structure.

The new suit is filed on behalf of an independent Chicago bookstore, but seeks to include any book seller who has purchased works from Hachette, HarperCollins, Macmillan, Penguin Random House, and Simon & Schuster from March 2017 onward.

“Amazon and the Big Five restrain competition in the sale of print trade books through highly restrictive most favored nation clauses (MFNs) in their distribution agreements,” the suit reads. “These anticompetitive provisions ensure that no rival bookseller can differentiate itself from, or otherwise compete with, Amazon on price or product availability in the sale of print trade books.

“It would increase the Big Five’s book distribution and therefore be in their economic self-interest to let Amazon’s rival booksellers gain market share by offering them lower wholesale prices or exclusive early releases," it continues. "But Amazon’s contracts with publishers cover practically all the potential avenues a competing bookseller may attempt to use in order to differentiate itself against Amazon.”

The suit comes as Amazon faces increasing antitrust scrutiny from Congress. Officials have proposed far-reaching reforms to antitrust laws to curb the power of tech giants across the board, which could overhaul competition law and possibly split up large tech companies.