Munster and Ireland rugby legend Anthony Foley died of an "acute pulmonary edema", an autopsy revealed Tuesday.
According to the autopsy, the 42-year-old Foley "had a heart rhythm disorder that caused an acute pulmonary edema", the Nanterre public prosecutor west of Paris told AFP.
Pulmonary edema is a build-up of fluid in the lungs that can lead to respiratory failure.
His death could therefore "be linked to a cardiac problem", the prosecutor added, without giving any further details.
Other toxicological analyses are under way, with results due in the coming weeks.
The prosecutor also issued a burial permit, with the body free to be released to the family.
Foley, the head coach of Munster, was found dead in his hotel room hours before his side were to play Racing 92 in the European Champions Cup in Paris on Sunday.
The robust backrow forward won 62 caps for Ireland, captaining the team on three occasions. He also led Munster to the European title in 2006.