NEW YORK (Reuters) - A Deutsche Bank (DBKGn.DE: Quote, Profile, Research) executive is suing a son and a brother of Delaware Sen. Joe Biden for at least $10 million (5.1 million pounds) over a deal they had to buy into a hedge fund, according to court documents.

Stephane Farouze, who is global head of fund derivatives for Deutsche Bank and lives in London, claimed that Biden's son Hunter and brother James broke a May 2006 contract and defrauded him after agreeing to buy his membership interests in New York-based Paradigm Companies LLC.

The lawsuit filed in New York State Supreme Court in Manhattan in June names Washington lobbyist Hunter Biden, James Biden, and James's former business partner Anthony Lotito as defendants.

On Wednesday, Farouze's lawyer Marlen Kruzhkov said that the Bidens "never had any intention of carrying out the agreement with my client".

He said the Bidens and their lawyers have not responded to the complaint.

Representatives for the Bidens could not immediately be reached for comment.

The lawsuit said that while the Bidens took control of the company, they never paid Farouze the cash they had agreed to pay.

Sen. Biden is a Delaware Democrat who was first elected to the U.S. Senate in 1972. He has been mentioned as a possible vice presidential candidate on Sen. Barack Obama's presidential ticket.

The lawsuit is the second accusing Biden's relatives of irregularities in their deal to buy hedge fund firm Paradigm. An earlier lawsuit was filed by Lotito in January 2007.

(Reporting by Grant McCool, editing by Phil Berlowitz)