Wednesday's court decision sparked widespread outrage in France with one feminist group saying it sent a "catastrophic message" that rape is permissible.
Ten men were acquitted in the case while four others were handed sentences ranging from one year to three years suspended for raping one victim, identified only as Nina, now aged 29.
Prosecutors had called for eight of the accused to be given sentences of between five and seven years.
The chief prosecutor for Créteil, near Paris, Nathalie Bécache, said the verdict does not take into account how the crimes were committed, nor the particularly serious physical and mental damage done to the two victims.
The two victims, who came forward six years after the rapes occurred, say they were repeatedly raped between 1999 and 2001 in Fontenay-sous-Bois, just outside Paris, where they lived.