Bastia striker Brandao was caught on camera assaulting the PSG midfielder after their Ligue 1 clash on August 16, leaving Motta with a broken nose.
The Ligue de Football Professionnel (LFP) subsequently sanctioned Brandao with a ban until February.
Bastia appealed the ruling, but the FFF confirmed on Thursday that the original suspension would stand.
"The Appeal Committee of the French Football Federation today confirmed the penalty originally imposed by the Disciplinary Committee of the LFP against Brandao," read a statement on Bastia's official website.
"The Brazilian striker remains suspended until February 15."
Brandao's actions were widely condemned, with PSG president Nasser Al-Khelaifi stating that the striker should be banned from playing football for life.