Eric Breteau and his girlfriend Emilie Lelouch were arrested when they turned up at the Paris court on Tuesday to hear the verdict. They had not attended the trial which took place between 3 and 12 December.
The four other defendants were given six month and one year suspended sentences, and the association itself was fined 100,000 euros and dissolved.
The Arche de Zoé operation was intercepted on 25 October 2007, while members of the group were preparing to board a specially-chartered plane to France along with 103 children who were wearing false bandages.
The couple said they wanted to save orphans from the deteriorating situation at the time in Darfur, but according to several humanitarian organisations, most of the children in question were from Chad, and had at least one living parent.
Breteau and Lelouch were said in court to have exploited families who took part in internet discussion forums on adoption.
When the couple met host families, they explained that adoption would not be immediate, but the prosecution argued that they used language which suggested that it was a possibility in the long term.
The couple and four other volunteers had previously been sentenced in Chad to eight years forced labour for attempted abduction. That sentence was then commuted to a prison term in France, before Chadian president Idriss Deby pardoned them in March 2008.