Fire, noise, fury, a sense of empty energy. And across town, a football match too. Do any of these randomly pitched autumnal Champions League fixtures mean anything? Probably not when you're Paris Saint-Germain and Barcelona, and the only game in town is risk-free TV income and a semi-guaranteed place in the knockout stuff.

But this was still a dazzling occasion at the Parc des Princes, where the champions of France and Spain played out a light, open, frictionless, exhibition-style game of football. PSG finished 4-2 winners, having been pegged back to 2-2 midway through the second half. But this was also a game where the score almost did not seem to matter, and where the only really hard message was the frailty of the Barcelona backline and PSG's thrilling attacking energy in these midweek A-games.

"Debris! Debris! DEBRIS!" the insanely loud PA announcer screamed into his mic before kick-off, in what appeared to be a poor-taste tribute to the current state of the nation's capital, although it may also have been "".

In the hours leading up to this game France's interior minister had specifically ruled out postponing the whole thing due to the ongoing state of civil unrest, the kind of statement that is no doubt intended to sound reassuring, but which also generates its own kind of whiplash.

Paris is burning. Paris is always burning. No, but Paris really is burning this time. The main site of the violence of the last few days is three miles east of the Parc, which lurks by the ring road in one of Paris's slightly inner quarters, rising up like a vast concrete alien doughnut in between the townhouses.

On matchday it required a degree of cognitive dissonance to take in these two opposing spectacles. On one hand the piles of charred bikes and the mass looting which has, in reassuringly Parisian style, seemed to focus on elite high-fashion brands. Chanel will rue the day.

In the middle of which Paris also hosted this glittering treat of a football match, stuffed with so many throwaway little delicacies, like an elite artisan patisserie. Before kick-off there were leaping tongues of flame, a laser show spectacular, and a vast tifo at one end showing a ghoulish PSG serial killer type attacking the Barcelona badge with his blood-soaked chainsaw. The message here seemed to be: we are confident. We believe in our process. And we will hack you to death.

From the start this was a high-grade, disarmingly open game. For Hansi Flick's Barcelona it represented a genuine test of method. Here we have an elite team that plays with a studied disregard for some of the tenets of positional defensive play. We will press forward and trust what lies behind. We will also give up on the basic idea of marking pretty much from the kick-off, as it turned out.

With one minute gone PSG should have scored. A quick diagonal passing move from right to left put Khvicha Kvaratskhelia in space. His shot pinged off a post and back to an offside Ousmane Dembélé, who shinned wide of an open goal.

There was a fury to PSG in those opening minutes, the front players finding angles and free channels. Pedri and Marc Bernal in central midfield took a while to settle for Barça. Bernal is pure La Masia, a baby-faced 19-year-old Catalan, misleadingly so, as he also has the physique of a rugby union flanker. And Pedri is of course the kind of footballer who glides through these occasions, so casual you half expect to look down and notice he's playing in flip-flops and holding a Calippo.

Before long Barcelona were making chances of their own, Dani Olmo setting off on a couple of surging deep runs, Anthony Gordon almost getting on the end of a cutback.

João Cancelo was booked with 16 minutes gone for a lunge on Désiré Doué, a disastrous state of affairs for any full-back faced with this nightmare of feints and fast-twitch feet. And two minutes later Dembélé was off, injured chasing the ball, replaced by Ferran Torres. Maybe he should play a bit more, get match fit.

Still the game just zinged from end to end. Raphinha had a close-range shot blocked by Matvey Safonov after a nice pass from Gordon. PSG had three shots blocked or saved in the space of six seconds on 28 minutes, Joan García saving brilliantly low down.

And on 38 minutes PSG deservedly took the lead. The goal was in keeping with the game, expertly hi-tech but also strangely easy and open. Lamine Yamal essayed an ambitious chipped clearance. João Neves took the ball back. It fell to Doué, and he had time to jink inside, feel the space around him, and shoot low inside the post.

PSG were bossing this by now, Kvaratskhelia running up and down the gears on the left, such a beautifully inventive presence, socks crumpled down around his ankles, all mooching straggly menace, as though the base player from Shed Seven has reinvented himself as a state of the art elite European inside forward.

By the break Barcelona were hanging on, overrun in midfield. And the second half was more of the same: mobile, relentless, high-grade product, lovely attacking interchanges, occasional large spaces in the Barcelona backline.

Doué forced another fine close-range save, played in by Vitinha. On 55 minutes Barcelona equalised, Xavi Espart galloping through the left side of the PSG defence and smashing a shot into the net off the hands of Safonov. The PA announcer gave the goal to Lamine Yamal, because, well, great branding. But it was Espart's first in Europe, the second of his career. He's 19, hyper-versatile, another dreamy Catalan youth-teamer.

Barça brought on Rodri, absent from the starting XI, Flick admitted afterwards, solely with the weekend's in mind. For a while order was restored, Rodri strolling around like the only grownup on the pitch.

But PSG always have tools to hurt you. Doué sliced open the right side again and crossed for Fabián Ruiz to hit the post from six yards out. From the corner Lucas Hernandez had the space to leap and produce a wonderful finish, thumped off the meaty part of the forehead high into the top corner.

Seven minutes later it was 2-2. This was a strange goal, scored by Lamine Yamal after a wonderful run in from the right and a lofted near-post finish that in the moment either looked like a mistake from Safonov or a moment of pure invention.

Two minutes after that it was 3-2 to PSG as the game kept on running to its own speed, this time a controlled first-time shot from Vitinha, seizing on a bouncing ball near the edge of the box. Ruiz added a fourth four minutes from the end.

The game against Lyon at the weekend will mitigate against the usual round of rotations, and injuries did begin to bite a little here. But PSG still finished like a machine built for these occasions, operating always with strength in reserve, and quite clearly the most potent midweek team in Europe once again.