More than one in two men -- 55 per cent -- from France and Italy admitted to cheating on their partners, along with one in three women.
The poll by Ifop, released yesterday, comes just a few weeks after "le scandale" in France, when President Francois Hollande was snapped leaving the home of actress Julie Gayet, on a scooter.
The photos led to the collapse of his relationship with long-time partner Valerie Trierweiler and a torrent of worldwide comment about French attitudes to fidelity.
Only 42 per cent of Britons and 46 percent in Germany admitted to having an affair at some point in their lives.
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"After all the noise about 'L'Affaire Gayet', and all the articles in the international press about the fickle nature of the French, this seems to confirm the cliches about latin males," Ifop director Francois Kraus told AFP.
Hollande and Italian leader Silvio Berlusconi, who was last year convicted of paying for sex with an underage prostitute at one of his infamous "bunga bunga parties", are "ultimately quite representative of their respective nations," added Kraus.
The more disciplined couples of northern Europe are not complete angels, though.
Some 53 per cent of Germans and 50 per cent of Brits have exchanged an illicit kiss, compared with 46 per cent in France, Italy and Belgium.
But it is the French that remain the most casual about flings, with 35 per cent saying they may cheat in the future, against 31 per cent of Germans and Spaniards, 28 per cent of Italians, and a quarter of Brits.