The row began back in the winter of 2015 when a French Catholics association sued Black Devine, the publishers for extra-marital affairs dating site Gleeden, over some provocative adverts that promoted its services to those willing to cheat on their partners.

“Contrary to anti-depressants a lover costs the social security system nothing,” read one of the bus stop adverts for Gleeden. 

“Being faithful to two men means you are twice as faithful,” read another advert placed at bus stops and Metro stations, and banned by the offended mayors of some towns in France.

“Fancy adultery. It’s your turn to play,” reads a line on the site’s web page, giving a flavour of the kind of provocative advertising that so-riled the Catholic association.

“We even found lists giving tips on how to cheat on your partner without being found out,” the association's lawyer Henri de Beauregard said.

The Paris-based Associations of Catholic Families group filed the complaint, “challenging the legality of the site and its advertisements.”

Adultery has not been a crime in France since 1975 but the association said the adverts were “publicly promoting infidelity and cheating” and a clear incitement to disrespect the French civil code, which covers marriage, and stipulates “mutual respect, fidelity, help and assistance between spouses.”

But the court in Paris threw out their complaint and ruled that there are instances where infidelity cannot be deemed an automatic legal grounds of divorce, notably when both partners prefer to engage in a libertine lifestyle or when the behaviour of one member of the couple excuses the infidelity of the other.

“It’s a victory for freedom of expression over these bigots driven by a desire to censure,” said Caroline Mécary, the lawyer for Black Devine.

“I cannot hide my pleasure at this decision,” she added. “The court was not duped… We were faced with an association that promoted a certain vision of the family, except that this vision was theirs only and they cannot impose it on everyone.

The Catholic association, which was ordered to pay €2,000 court costs to Balckdevine, vowed to appeal.