Messi will play his last match for the club against Clermont this weekend.
The 35-year-old joined PSG from Barcelona on a free transfer in the summer of 2021 and has won two Ligue 1 titles at the Parc Des Princes.
However, the much craved Champions League title did not arrive in Messi's two seasons in France as PSG suffered round of 16 exits in both of the Argentine's campaigns.
Messi has scored 21 goals and provided 20 assists for PSG this season.
Last month, Messi was suspended for two weeks by PSG for embarking on an unauthorised trip to Saudi Arabia.
“I will take away that I have had the privilege of coaching the best football player ever, Leo Messi,” said Galtier in remarks published on the club’s website, psg.fr.
“Saturday will be his last game at the Parc des Princes. I hope he will be welcomed in the best way possible.”
He has always been available, always present in the training sessions.
“Despite the remarks or criticisms that I don’t think were justified at all, he has always been at the service of the team, both as a provider of assists and as a goalscorer.
“He is 35 years old, there was a World Cup in the middle of the season. His stats outside of the World Cup, correct me if I am wrong, but I think he is on 21 goals and 22 assists, which means he has (contributed) 43 times this season.”