PSG were 10 points ahead in late February but they have now lost their last two games in their worst start to a calendar year in 22 years. On Saturday, they visit Nice, who are on a 12-match unbeaten streak, although they drew their last four games.
Second-placed RC Lens will be next up for PSG, who have already been eliminated from the Champions League and the French Cup.
Lens will provisionally move within three points of PSG later on Friday if they beat Racing Strasbourg at home.
“These are important matches. Nice are on a huge unbeaten run since (coach) Didier Digard took over. Then we will be hosting Lens, but first there is Nice,” Galtier told a news conference on Friday.
“We are all aware that we must do more, including myself. We must also show more personality and have a lot of pride. Our situation is not acceptable. We must not act, but react.”
Galtier warned that PSG’s lead was not a guarantee they would secure the title at the end of the season. “We obviously have to get out of this spiral. There is an 11th title at stake for Paris St Germain. That’s what I told the players, we have a six-point lead. But what do we do with these six points? Do we leave ourselves in a deadlock or do we react?”
Forward Kylian Mbappe, who is suffering from hip pain but will be available for Saturday’s game, criticised the club on Thursday after it featured him in a video to promote season ticket sales, without informing him how the interview would be used.
“It’s very difficult to comment on, it concerns Kylian and the club. Kylian was in a very good mood this morning, he was smiling, he cut short the training session with hip discomfort, but it will not compromise his participation in the Nice game,” said Galtier.
“I know there have been a lot of discussions between the management and Kylian. The incident, or misunderstanding, has been cleared up.”
