After three straight draws in all competitions and complaints from Mbappe about his role in the team, Galtier abandoned his 3-4-2-1 formation for a 4-3-1-2 as PSG bounced back and won two games on the trot, including a victory over rivals Olympique de Marseille.
"We changed our system in the last two games for various reasons. We wanted to see how we could be more dangerous and how to have an attacking trio playing closer to each other," Galtier told reporters ahead of Tuesday's Champions League Group H game at home to Maccabi Haifa.
PSG will guaranteee a place in the last 16 with a win.
"We played two games with that system. But no matter the system, you have to run a lot. Even if tomorrow we were to play with this system, we still have to rely on each other's efforts.
"It's an advantage to have two systems... It is true that there is this reflection about how to best position our three attacking players, players that any coach would dream of having. It's up to me as a coach to give them the best conditions."
Haifa shocked Juventus earlier this month with a 2-0 victory -- their first win in the Champions League in two decades -- and Galtier said he was not surprised by the Israeli side's quality.
"They are well organised, alert and punchy. They have technical players. They are aggressive ... and have players who attack. We were hindered for 30 minutes (in the reverse fixture which PSG won 3-1)," Galtier said.
"They beat Juventus with a different system and that shows the quality of their coach."
