Two Las Vegas clubs have been put on notice for allowing Paris Hilton’s underage boyfriend into their establishments on New Year’s Eve.Tao Asian Bistro in The Venetian and Body English at the Hard Rock Hotel received warning letters last month from the Clark County Business License Department after investigators determined that Stavros Niarchos, 19, was allowed into the clubs.

Hilton, co-star of “The Simple Life” TV reality series, recently celebrated her 25th birthday.

Both clubs were told they had violated county code, but were not issued citations because operators had cooperated with county agents, the letters said.

A security guard caught on a surveillance tape escorting the couple into the club was fired and the doorman who did not ask Niarchos for identification was suspended, said Jim Bowen, vice president and chief financial officer of the Hard Rock Hotel.

Several years ago, the resort made news when it ejected an underage Britney Spears.

Before heading to Body English, Niarchos had been denied entry to Tao. The club then opened an adjoining bistro and “effectively created a nightclub environment,” Business License Director Jacqueline Holloway wrote to Tao co-owner Rich Wold.

“Tao maintains a strict door policy and the staff never allows patrons under the age of 21 into the nightclub, regardless of their celebrity or status,” the club said in a statement.

Tao is not owned or operated by The Venetian hotel-casino.