PARIS — In a country recently transfixed by the trial of a famous politician that revealed details of his orgy escapades, and where the president was found to be cheating on his live-in partner, an ad promoting extramarital affairs might not seem like such a big deal.

But even in famously libertine France, the latest advertising campaign — evoking the temptations of Eve with a partly eaten apple — for a dating website geared to married women looking for affairs has spawned a backlash and a national debate.

The ads for the dating website Gleeden, which bills itself as “the premier site for extramarital affairs designed by women,” were recently splashed on the backs of buses in several French cities. Seven cities decided to withdraw the ads, and opponents have mobilized against them on social media, providing the latest example of a prominent cultural divide in France about the lines between public morality, private sexual conduct and the country’s vaunted freedom of expression.

Last month, the Catholic Family Associations filed a legal complaint against the site’s American publisher, Black Divine, in a Paris superior court. The Catholic group said the ad was crude and immoral and a reckless breach of an article in the civil code.