Macy's is trying to block Amazon from advertising atop its Herald Square store

Macy’s is embroiled in a legal battle with its landlord to prevent Amazon from marketing on a billboard that sits on top of its most iconic flagship store.

The department store chain is asking New York City-based Kaufman Organization to stop a potential deal with Amazon to use the billboard atop its storied Herald Square location, according to a lawsuit filed in state Supreme Court in Manhattan.

Macy’s is claiming that any advertisements from its online competitor would cause “immeasurable” harm to its business, the complaint said.

“The damages to Macy’s customer goodwill, image, reputation and brand should a prominent online retailer (especially Amazon) advertise on the billboard are impossible to calculate,” Macy’s said in court papers that were reviewed by CNBC.

Macy’s has been advertising its business on the billboard for longer than half a century. But the lease for the space recently expired in August, and Macy’s is claiming it failed to come to an agreement with Kaufman. Kaufman was already in talks with Amazon by that point, according to the complaint.

Macy’s, however, is claiming that its original lease on the billboard space included a provision that barred any other retailers from advertising on the billboard, indefinitely.

Representatives for Amazon and the Kaufman Organization did not immediately respond to CNBC’s requests for comment.

“Since the early 1960s Macy’s has placed a billboard sign on the building adjacent to our flagship store at the corner of Broadway and 34th Street,” a spokeswoman for Macy’s told CNBC in an emailed statement.

“Macy’s continues to have rights relating to advertisements at that location,” she said. “We expect to realize the benefits of these rights and have asked the court to protect them. As the matter is in litigation, the company will not have any further comment.”

Crain’s New York first reported on the court battle.