Thomas Tuchel believes it is clear that Neymar has felt the effects of Paris Saint-Germain's recent poor run as the French Football Federation (FFF) opened proceedings against the forward.
The Brazil international let his emotions get the better of him following the penalty shoot-out defeat last week as he appeared to punch a fan in a scuffle on the way to collect his runners-up medal.
The FFF could now hand Neymar a hefty suspension - reportedly between three and eight matches - and coach Tuchel admits the world's most expensive player is struggling.
"We all feel that Neymar is sad, he's not happy right now," Tuchel told a news conference ahead of Saturday's home clash with Nice.
"Neymar hates losing and, of course, he is sensitive to everything that is said about him. It has an influence.
"I can only say it is easy to judge someone like Neymar, who has a very big heart. We would like him to show his heart. That would be good for us."
PSG will be without Kylian Mbappe in their next clash, against Nice, after his own three-match ban for a red card in the final was confirmed.
Tuchel was unsure of the involvement of Layvin Kurzawa and Edinson
“We're going to wait and see if Kurzawa and Edi [Cavani] are available tomorrow for Nice, Thiago Silva, Thilo Kehrer and Thomas Meunier are absent, Kylian [Mbappe] is suspended.
“We are currently in a weird period with many players still absent, but we have overcome many obstacles with a small squad all season.”
With PSG going through such a tough period in terms of results, Tuchel was asked if he expects a rough reception from fans this weekend.
“Yes,” the German replied. “It's possible. I don't really know if it helps us but it's possible and we have to accept it because we lost.”