A French health insurance provider ruled Xavier's death was a workplace accident, a decision that TSO attempted to appeal, stating the employee's death "occurred when he had knowingly interrupted his mission for a reason exclusively dictated by personal interest, independent of his job, after he has an adulterous relationship with a ideal stranger", court records show.
TSO also argued Mr X was not in the hotel room it had organised for him.
The employee, identified as M. Xavier, was in Loiret, a province south of Paris, on business for railroad company TSO on February 21, 2013, when he suffered a fatal heart attack after having sex with a woman at her home, according to court papers posted to LinkedIn by attorney Sarah Balluet and translated to English.
But French judges rebuffed TSO's claims, arguing that a worker remains an employer's responsibility when they travel on a business trip, even when they are off duty.
He died at a hotel during a trip to central France in 2013, as a result of what the employer called "an extramarital relationship with a flawless stranger".
Therefore the reason for his death was not "attributable to his work but to the sexual act he had with a complete stranger".
A previous court ruled in 2016 that "a sexual encounter is an act of normal life like taking a shower or eating a meal", which was upheld by the appeal court in May.
An employee on a business trip is entitled to social protection "over the whole time of his mission" and regardless of the circumstances, it said.
The Court of Appeal in Paris ultimately chose to uphold the insurance provider's original decision, noting "it is common ground that sexual intercourse is an act of everyday life".