Hundreds of ultras, mostly dressed in black, were spotted marching through Highbury Fields a few hours before the match.
New footage has since gone viral on TikTok showing that some of them also turned up outside a local 3G pitch, completely transforming the atmosphere.
The group lit flares and belted out PSG chants behind one of the goals on a small-sided pitch. One of the PSG fans led the chanting with a megaphone, while another man was seen sitting on top of a high metal fence.
Some of the players embraced the ultras and were seen laughing and singing along, while others just looked shocked.
Footage of the incredible scenes was shared on TikTok by one user, who wrote: 'PSG ultras show up to a local football game before their game vs Arsenal. They made the council pitch feel like Parc des Princes'.
One comment then read: 'That’s class tbf, you’d buzz off playing with that going on surely'.
Many other fans commented how they would have loved to have been playing in that atmosphere.
One wrote: 'I'd play the game of my life'.
Another added: 'This would turn me into prime Ronaldo'.
A different fan commented: 'Would've had to score and run over to them to celebrate like it's a stadium'.
Around 3,000 PSG fans came to London for Tuesday's Champions League game at Arsenal
PSG lost 2-0 to Arsenal in Tuesday's headline event.
Kai Havertz and Bukayo Saka got the goals for the Gunners, who now have four points from two games in this season's Champions League.