The photo showed a soldier with a rifle in his hands wearing a patch on the right arm carrying the French flag, number 32 and the insignia “Meine Ehre heißt Treue” (My honour is loyalty), the motto used by SS soldiers during the Nazi regime.
It is unclear what the number 32 refers to, although it may refer simply to the soldier's military unit.
The photo was part of nine photos posted on the French army’s facebook page before it was taken down again. However, several media organisations took screen captures of the photo before it was removed. French news agency AFP also found what appears to be a photo of the same soldier wearing the same patch on 17 December.
"This is an unacceptable attitude that doesn't reflect the reality of the armed forces," said army spokesman Colonel Gilles Jaron.
He said the patch is not part of the army’s uniform, adding that it was an isolated case and that the army is looking for the soldier in order to suspend him.
Earlier this year, the French army faced controversy when a soldier in Mali was photographed wearing a scarf resembling a death mask.
And in 2008, three French soldiers were photographed making a Hitler salute while wrapped in a Nazi flag.