It was a real statement of intent from this summer's big spenders who signed Brazilian Neymar and teenage sensation Mbappe.
Neymar, Kylian Mbappe, Edinson Cavani's double and a Mikel Lustig own goal consigned Celtic to their record home European defeat and propelled PSG to the top of the table on goal difference from Bayern Munich, who they host on match day two.
It was a real statement of intent from this summer's big spenders who signed Brazilian Neymar and teenage sensation Mbappe in a bid to make a real impression on the competition.
After four consecutive seasons of reaching the quarter-finals, PSG fell at the round of 16 last season when they capitulated against Barcelona after winning the first leg 4-0.
It was a result that convinced their Qatari owners to break the world transfer record to bring Neymar to the French capital.
The 6-1 defeat to the Catalan giants in the second leg was a humbling for PSG but Emery says they are approaching this season's campaign with a renewed confidence.
"We did learn from the past and what happened last year. We have worked really hard to improve things within the team," the Spanish coach said.
"I think my team showed a lot of character. What I was really pleased with was the fact we were in control with the ball and without the ball.
"Of course we have added to the team but it is more about all the people working together. As far as this is concerned I am really, really happy."
The French side's formidable front line terrorised the Celtic defence and Emery warned they would only get better.
The PSG coach singled out Mbappe, who PSG have an option to buy from Monaco for a fee that could reach 180 million Euros, for praise.
"This is what he needs at the moment. He wants to be a great player and he is going to grow up into that role," Emery said of the 18-year-old who scored his second goal in two games.
"They have only played a few games together... but the key is that the team is going to improve more and more."
Celtic manager Brendan Rodgers said his side, who conceded five at home for the first time since Rangers beat them 5-1 in September 1960, said his side weren't at the same level of the French superstars.
"You have to give credit to them. They are a really special team and they are going to be close to winning it for sure," the Northern Irishman said.
"This is a level where you have to look after the ball, and you have to make the ball work for you, and in the first half we didn't do that."