According to French publication 'L-Equipe', Mbappe was sent home after a confrontation between him and the 33-year-old defender last Tuesday.
The incident will only increase speculation surrounding the youngster's future with the French champions, as PSG reportedly line up an £163m offer.
Technical staff had to act firmly to remove the 18-year-old from the training session after he initially refused to leave the pitch.
The pair were left out of Monaco's matchday squad for the victory at Metz on Friday. When asked about Mbappe's absence, manager Leonardo Jardim said, 'it is our duty to protect him at the moment.'