French President Jacques Chirac thought he had taken a call on Friday from the new Canadian prime minister - but found himself the victim of a radio hoax.
Jacques Chirac finally took the gag in good humour
The pair of hoaxers, known as the Masked Avengers, rang the Elysee Palace from their base in Montreal.
Mr Chirac congratulated the caller he thought was Conservative leader Stephen Harper on winning Monday's election.
When impersonator Marc-Antoine Audette finally gave his true identity, the president burst out laughing.
Audette and his partner in crime Sebastien Trudel work for the CKOI station, Montreal's most popular with more than one million listeners.
Audette said: "It was the first time Sebastien and me had spoken to a head of state."
As Mr Harper and Mr Chirac had yet to speak, "We said, why not, we'll give it a go and we're delighted that it worked," Audette said.
Mr Chirac began by saying: "I would like to offer my congratulations for your election victory. We have excellent relations and I'm sure they'll carry on in the best spirit."
Audette, in a deliberately thick French-Canadian accent, then complained that French newspapers had portrayed him in a bad light.
Mr Chirac responded: "You can't prevent newspapers from saying any old stuff. That's true in France and it's true in Canada."
"Exactly Mr President, liberty, equality and fraternity. Amen," said Audette.
Mr Chirac, 73, then invited "Mr Harper" to visit France.
When the gag was revealed, the president laughed, saying: "Oh right, I understand. In any case, please know that my friendship for Canada and the new Conservative government is a real and unequivocal friendship."
The hoaxers have in the past targeted Tiger Woods, Bono, Donald Trump, Paul McCartney and Janet Jackson.