As the PSG squad walked up to receive their runners-up medals, Neymar initially pushed a supporter's hand away as he tried to record him on his mobile phone.
The visibly frustrated Brazilian, who had returned last week from a three-month injury layoff, then appeared in the video to jab at the spectator before walking away to collect his medal.
Neymar posted a message on Instagram after the game, saying: "Nobody likes to lose. Everyone who knows me knows how competitive I am and how much defeat shakes me.
"But losing is part of an athlete's life, it makes us grow, makes us think, makes us better. Happy to be able to play again, to score again and feel good on the pitch but the biggest feeling today is one of sadness."
Reuters has contacted PSG for comment.
Earlier this week, Neymar was suspended for three Champions League games for insulting match officials following the French side's elimination from the Champions League. PSG have qualified for next season's Champions League by winning the Ligue 1 title.
(Reporting by Rohith Nair in Bengaluru; Editing by Toby Davis)
