In the same verdict, the Paris criminal court also handed top division club Montpellier's owner Mohed Altrad an 18 months suspended prison sentence, AFP said. The court was not immediately available for comment.
Laporte was accused of undue influence in securing a role for his friend Altrad, whose construction company sponsors the France jersey. Both men denied any wrongdoing.
Le Parisien reported Laporte was found guilty of several offences including illegal taking of interest, influence peddling, corruption and embezzlement.
He will be banned from holding any position in rugby for two years, the paper added.
World Rugby added in a statement that Laporte, who also holds the position of vice-chairman in the organisation, will no longer perform his duties until further notice.
"World Rugby notes the decision by ... Laporte to self-suspend from all positions held within its governance structures with immediate effect following his conviction by the French court in relation to domestic matters, and pending his appeal," they said.
Next year's Rugby World Cup will be held in France from September 8 to October 28.
The verdict can still be appealed.