French President Nicolas Sarkozy called Israeli Prime Minister Benjamin Netanyahu a "liar" in remarks to US President Barack Obama overheard by journalists at the G20 summit in Cannes last week.
"I can't stand him anymore, he's a liar," Mr Sarkozy said in French.
"You may be sick of him, but me, I have to deal with him every day," Mr Obama replied.
The two heads of state were engaged in a private conversation on November 3rd when, according to French website 'Arret sur Images', Sarkozy's communications staff distributed journalists with sound receiver boxes to follow official speeches.
The journalists were reportedly told that they would have to wait for headphones because otherwise they could eavesdrop the private chat between Obama and Sarkozy. Several among them then plugged in headphones from other equipment, including their mobile phones, and picked up the behind-doors exchange between the two presidents.
Arret sur Images quoted one of the journalists present, who was not named, as saying:"In the time it took for the Elysée staff to realise what was happening, three minutes must have gone by."