When the Qatari sovereign fund bought PSG, hopes were high that the fans would leave behind their reputation for racism and thuggery. But after France's richest club won the league, celebrations turned ugly as supporters clashed with riot police in Paris.
Violence taints Qatar's PSG dream
And what better setting than the Trocadero, just across the Seine from the Eiffel Tower, to fete the newly super-rich, newly glamorous Parisian football team after a famous achievement? Unfortunately, the occasion degenerated into a violent confrontation between police and hundreds of those present.
To the well-informed but busy reader, a headline about trouble involving supporters of Paris Saint-Germain would induce little desire to read on.
Here, after all, is a club whose fans, a sizeable minority of them, have worn their reputation for thuggery, racism and general nastiness as a badge of honour. If a game promised little opportunity for combat with rival supporters, they would simply nominate a battleground on which to fight among themselves.
All of this was meant to change when the Qatari sovereign wealth fund bought a controlling interest in 2011 and outright ownership nine months later. A different kind of PSG would evolve.
And when lavish investment in players and coaching staff enabled Paris's only senior club to accomplish a first top-flight championship in 19 years, a glitzy celebration was irresistible.
Huge Qatari investment had turned French football upside down, making the world outside care which team won a league previously considered so lacklustre and under-resourced that the better players automatically found greener grass beyond France's borders.
The obvious location for such a celebration was the Parc des Princes, PSG's home ground. But the shirts the players wear bear the image of the Eiffel Tower and that symbol of Paris offered an impressive backdrop for fit, sharply dressed athletes gathered on a podium.
What happened next brought city, club, country and sport into grim disrepute. Ten thousand or so people gathered to see the stars - the Swedish striker Zlatan Ibrahimovic and the soon-to-retire David Beckham among them. The team arrived an hour later than expected and were gone within minutes as exuberance in the crowd turned to violence.
As the atmosphere rapidly grew more unpleasant, riot police intervened, stones and other missiles were lobbed at them and tear gas was fired back.
Anyone who has been present at a Parisian riot knows the sequence. Aggressive young men start making trouble and officers respond in a way that has little to do with cosy notions of community policing.
Among the troublemakers were young men wearing PSG shirts and young men who had simply come in from the unruly suburbs for a spot of action. Despite the reputation for racism that PSG hooligans possess, and in many cases hold dear, there were black faces as well as white.
Police spotters identified missile throwers and arrests were made. As subsequent court appearances demonstrated, the innocent as well as the guilty were detained in the process. In the first court hearings, three Brazilians who claimed they were merely caught up in events and ended up victims were given the benefit of doubt and acquitted.
There was talk of the violence being stirred by disenchanted supporters, the so-called "ultras", who have been made unwelcome as the gentrification of PSG has gathered pace. These relics of 1980s football lawlessness are now considered an embarrassment in any stadium and they find them harder and harder to penetrate.
Or do they?
The Italian Serie A club Roma was fined ?50,000 (Dh236,000) this month after some of its supporters chanted racist slogans in a match against AC Milan. In England, fans of Newcastle United rioted in the centre of their city after a heavy defeat to their bitter local rivals, Sunderland. Television cameras captured appalling behaviour by followers of Millwall, long notorious for crowd misconduct, in an FA Cup semi-final at Wembley Stadium.
And three nights after the ugly scenes at the Trocadero, a chilling France 2 documentary reported on football hooliganism in Poland as well as among PSG supporters. One self-confessed Parisian thug, his face disguised, talked of a "natural obsession" to fight.
The disturbances led to questions about the resentment felt by "ultras" who claim they have been excluded from PSG in favour of more affluent, more chic and emphatically more peaceful Parisians. It transpired that while some of those detained were long-serving PSG fans, others were opportunists.
However, it is a sad reality that football louts have not disappeared. The chances of being able to cause trouble in and around stadiums have diminished, but the evidence shows they have not been eliminated. And individuals bent on conflict are often resourceful enough to know how and where to orchestrate it.
None of this is what Qatar Sports Investments wants from its costly, high-profile engagement in the football played in France's capital.
The interior minister, Manuel Valls, went on the air to say: "French football is still sick."
Neutrals observed that for all the score-settling gangland murders that make Marseille seem like a Chicago caricature, France's second city - and, currently, second footballing power - somehow avoids such manifestations of the sport's darker side.
For Nasser Al Khelaifi. a former tennis professional who is now the president of PSG, the events represented a grim moment "after all we have done in two years to bring happiness to Parisians".
He pointed out, in an interview with the daily newspaper Le Parisien, that no one - PSG, police, media - expected such disruption of a feel-good event. He promised that any season ticket holders convicted for their part in the fracas would be banned from the stadium.
That Mr Al Khelaifi also felt the need to reaffirm Qatari commitment to the club and city spoke volumes for the sense of collective shame felt by those associated with PSG. The violence, he said, would have no impact on Qatar's investment in the club. "Absolutely not . it will just motivate us to be even stronger in terms of security. No one will halt our project."
Beckham, already preparing to make his announcement ending an illustrious playing career, was said by Mr Al Khelaifi to have been moved by the joyous scenes that initially greeted the team on their arrival at the Trocadero.
It is a memory he may consider worth keeping. It is unlikely that any future trophy-winning player of PSG will be given the chance to attend such a ceremony in the heart of the city of romance and light.