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Marseille-born Galtier, who began his playing career with the south-coast team, leads PSG into a Classique at the last-16 stage of the Coupe de France.
It is a meeting of the top two teams in Ligue 1, and PSG will be back in Marseille later in the month for a clash in league competition.
The Parisians also face Monaco and Lille in February, and it hosts the first leg of the keenly anticipated Champions League last-16 showdown with Bayern Munich next Wednesday (AEDT).
Asked about pressure during what is his first term at the helm, Galtier said: "There is pressure from the moment you sign the contract. You have to get results.
"It is a month with a lot at stake. We will be playing in three competitions: the league, then tomorrow is a knockout game, and then the tie against Bayern Munich which everyone is looking forward to. That is also a knockout. There is a lot at stake and there are a lot of expectations this month."
Sergio Ramos and Neymar are available after injury, but Kylian Mbappe remains absent with a thigh problem.
Lionel Messi, after his winning goal against Toulouse on Sunday, will again be a player PSG look to for leadership.
"It is not just a last-16 tie but a Classique," Galtier said.
The coach is taking unusual measures to keep his mind on the job, even apparently snubbing family.
"I am trying to close everything from the outside that could be reaching my phone from family members so that I can stay focused on preparing for the game," Galtier added.
"We will need to be ourselves and play at our best level. We will need to be very good technically and have the ability to play under pressure from the opposition.
"Regarding the context, all my players have played in these sorts of games before."
It is this reason that encourages Galtier to believe his team should be able to cope with what should be a raucous atmosphere, feeding tensions on the pitch.
"We can't be overcome by dissent," he said. "There could be incidents on the pitch. It is the biggest game of the year for many people, so we need to stay clear-headed.
"I don't tell them to stay calm, because if you are calm you will fall asleep. You simply need to be clear-headed and play with quality."