Galter said ahead of PSG`s game against Clermont on Saturday that it would be Messi`s last match at the Parc des Princes.
"I had the privilege of coaching the best player in the history of soccer," Galtier said. "This will be his last match at the Parc des Princes, and I hope that he will receive the warmest of welcomes."
Messi`s departure is believed to be a mutual decision, with his contract effectively allowed to run down since January. The development comes days after PSG suspended the seven-time Ballon d`Or winner following his trip to Saudi Arabia without the club`s permission.
Messi has a commercial contract with Saudi Arabia to promote tourism in the Middle Eastern country and has been linked with a lucrative move there at the end of the season. There has also been talk of a return to Barcelona, where he spent the majority of his career, or to the United States to play in MLS. Barring a late change of heart from him or PSG, this seems certain be his final season in the French capital. His suspension and news of his exit comes at a time when PSG is embroiled in an increasingly fraught French league title race.