Marine Le Pen, leader of the FN, expelled 20-year-old Alexandre Gabriac from the party after a photograph of him saluting a Nazi flag was published on a magazine Web site, Radio France Internationale reported.
Gabriac, who represented the FN on the Rhone-Alps regional council, claimed the picture was a montage.
Le Pen also said skinheads and people wearing combat gear would be banned from the party's annual gathering to honor Joan of Arc on May Day.
Le Pen said she ordered the ban because "we have been victims, and still are sometimes, by the way, of a certain number of provocateurs who come to get cheap publicity."
RFI said Le Pen wants to dissociate the FN party from its past reputation for Nazi sympathies.