Billionaire Paul Allen sues to get military tank

Paul Allen takes his security seriously-including, it seems, a fondness for military tanks.

The billionaire is suing a company he said agreed to sell him a World War II German Panzer but failed to deliver it, according to a report in The Register.

Read More Fleet of military tanks up for auction

The report said one of Allen's companies-called "Vulcan Warbirds"-claims it paid $2.5 million for a 28-ton Panzer IV. Allen said he planned to include the tank in the Flying Heritage Collection, his military aircraft museum in Everett, Washington.

Yet the court filing said that after making the deal with Auctions America, the tank was never delivered.

"Auctions America has failed to honor our agreement and yesterday we sued it and the Collings Foundation, the former owner of the tank, to enforce our contract," Vulcan said in a statement. "We look forward to restoring the Panzer IV Tank and having it join our Sherman tank and other historic military aircraft and vehicles at the Flying Heritage Collection."

Read More Staging your mansion for $45,000

An executive with the Collings Foundation, which was the seller of the tank, said that they never had a deal.

"We do not have an agreement to sell a Panzer IV to Paul Allen or Flying Heritage Collection or Vulcan or any of his companies," director Rob Collings said. "I heard the comment made from someone at Flying Heritage Collection that this was a case of sellers' remorse. No, it was not. We didn't ever sell it."

Read More Fights over superyachts, once classy but now ugly

For its own part, Auctions America told CNBC, that it was "honored to present the Littlefield Collection, one of the world's leading military collections. Unfortunately, we now find ourselves caught between two of the hobby's most important collectors. We are diligently working with both parties to reach an amicable resolution."

To read the full story in The Register, click here.

-By CNBC's Robert Frank