PARIS - President Nicolas Sarkozy used to take on foul-mouthed rappers. Now, his eldest son appears to be embracing them.

French rapper Poison, known for his expletive-laden lyrics and his fierce criticism of the conservative leader, said Pierre Sarkozy helped produce some of his upcoming album -- and even contributed the lyrics for one of its tracks.

In an interview last week with hip-hop radio station Generations 88.2, Poison said he didn't realize who Pierre Sarkozy -- who goes by the pen name "Mosey" -- was until after he agreed to work with him.

"When I found out, I swear I went ballistic," Poison said. "The worst thing is that ... I found out maybe six, seven months ago, and I've known the guy for the last five years. He's a friend."

Poison made clear that his relationship with Pierre Sarkozy hadn't changed his opinion of the president, whose 2003 pledge to crack down on offensive rap lyrics angered many people.

"I'm not a fan of Sarkozy," Poison said, concluding with an expletive.

During his tenure as interior minister, Sarkozy complained about what he called the racist and anti-Semitic content in songs by the French hip-hop group Sniper.

Pierre Sarkozy, who is in his early 20s, is one of the French leader's three sons. He lists the Poison track "La Rue" as one of his credits on a My Space Web site with what appears to be a picture of the president's son. On the page, "Mosey" describes himself as a "young Parisian producer."

Sarkozy's office would not comment on the radio interview, saying it involved the private life of his family.