Click through to see Mbappe's reaction to coming off against Montpellier.
"Neymar's night is a distraction, obviously, and I always protect my players".
"The substitution of Kylian or Ney's birthday are distractions, it gives the impression that we are not serious", the German coach was quoted as saying by L'Equipe. "They become important when we talk about them a lot".
Neymar needed lengthy treatment after being injured by Montpellier's Arnaud Souquet towards the end of the first half and angrily remonstrated with the fourth official in the tunnel at half-time.
Neymar warmed up with a shirt bearing the name of Kobe Bryant and the number 24 of the basketball star who was killed in a helicopter crash last weekend.
Neymar then approached the official at the interval, by which time PSG were leading 3-0, in an incident caught on camera by Canal+.
Mbappe netted his 36th goal at the Parc des Princes in 34 matches in the 57th minute with a cool finish after being played through by Neymar.
"Sunday is not good [for Neymar's birthday party]", Tuchel said. "I am not angry, just sad as it was unnecessary". For me, it is a shame because it makes us seem like we are neither 100% concentrating nor professional. I will always decide the technical aspects. "This is football, not tennis, and you have to respect everyone".
Paris Saint-Germain's French forward Kylian MBappe (L) is congratuled by Paris Saint-Germain's Brazilian forward Neymar after scoring a goal during the French L1 football match between Paris Saint-Germain (PSG) and Montpellier Herault SC at the Parc des Princes stadium in Paris, on February 1, 2020.
Mbappe and Tuchel were then picture arguing for a few seconds before the former made his way over to the bench without acknowledging anybody on the bench.