On Sunday, Marseille play Paris Saint Germain at Stade Velodrome in the latest instalment of French football's most intense rivalry. Political, social and cultural issues all feed into this fiercely contested fixture, while, in 1993, it was impacted by one of the biggest scandals in the sport's history.

The great French cities of Paris and Marseille have rarely seen eye-to-eye; their well-established rivalry is informed by historic debates about power and geography. But curiously, the fact that PSG were founded as recently as 1970 dictates that their internecine football warfare is one of Europe's more embryonic grudge matches.

Indeed, it has only genuinely festered since the late 1980s to early 1990s, with the arrival of the infamous Bernard Tapie as president of l'OM and television station Canal+ as owners of PSG. Buoyed by wealth, and calling on the two biggest supporter bases in the country, the football clubs of the two disparate cities began to embody the strained regional divide in the sporting sphere.

Rivalry was nurtured on both sides, but Marseille proudly accelerated away from their northern rivals when becoming the first French side to win the European Cup in 1993, the first season of the Champions League. A solitary goal from Basile Boli defeated Fabio Capello's great Milan side of Van Basten, Maldini, Baresi and Rijkaard in Munich, and just three days later, Marseille secured the Ligue 1 title for the fifth consecutive season when defeating none other than their rivals PSG, Boli again on target with a famous header.

But even in the midst of a glorious week, deep controversy had erupted. Two days before that crucial victory over PSG, who finished second in the table, an investigation had been opened in response to allegations of attempted match-fixing in a 1-0 win over Valenciennes that preceded the Milan tie. At the centre of the storm, though he initially deflected scrutiny, was Tapie, a man described by Le Figaro as arriving back in Marseille after the Milan victory "like a Roman general at the head of his legionnaires". But within two years of that epic triumph, he was in jail, a football outcast.

Tapie was no stranger to attention, though. Raised in the North-East Parisian suburb of Le Bourget, he became chairman of adidas and in 1992 also achieved political recognition when appointed as the socialist urban affairs minister in the government of Prime Minster Pierre Beregovoy. As an independent candidate, he had even been endorsed by President Francois Mitterrand and it was rumoured that, as well as coveting the position of major of Marseille, he had aspirations of national office in future. It was not for nothing that Tapie was being compared to Silvio Berlusconi, the man whose Milan side had been defeated in Munich.

Just seven weeks after his ministerial appointment, though, Tapie was forced to resign the post after being charged in a fraud probe relating to alleged payments involving Toshiba. He was reinstated in December 1992 after charges were dropped, but scrutiny over his conduct would not abate during a string of controversies over the following years, and it was not restricted to his political and business dealings. Marseille's title win of 1992 had also been overshadowed by allegations of fraud relating to payments to former players, and it was against this unpalatable backdrop that one of football's great scandals erupted.

Seeking to ensure Marseille approached the Milan final in the best shape possible, and without sacrificing the club's league campaign, Tapie plotted to pay off certain Valenciennes players prior to the Ligue 1 fixture on May 20. He instructed general manager Jean-Pierre Bernes to set-up the deal, and with Marseille's Jean-Jacques Eydelie as a conduit, Bernes spoke over the phone to Jacques Glassmann, Jorge Burruchaga and Christophe Robert in order to offer them money to ensure they took it easy in the league fixture.

As Eydelie later revealed in a book published in 2006: "Bernard Tapie said to us, 'It is imperative that you get in touch with your former Nantes team-mates at Valenciennes (there were two of them including Burruchaga). We don't want them acting like idiots and breaking us before the final with Milan. Do you know them well?"

Robert took the money, Burruchaga was later charged with responding positively to the offer while not actually receiving any money, but Glassmann blew the whistle and informed the Valenciennes hierarchy. As rumours gathered pace, and investigations were launched, Tapie was forthright in his denunciation of the probe. "I'm sickened," he said after his side won 1-0. "It's a lynching, and there's not the slightest proof of guilt."

However, the controversy began to unravel further on June 30 when Robert admitted taking a bribe, declaring ominously: "The world of football is much more rotten than people like to think." He led police to his aunt's garden in the Dordogne town of Perigueux and dug up an envelope containing 250,000 Francs (£30,000). According to Robert, he chose the unusual place to hide the cash as "that money stank so much that I threw it in a hole".

With Le Monde reporting that the envelope and paper clips buried with the package matched those in Marseille's offices, and Burruchaga and Robert charged by officials, the net was closing on Bernes, at least. Placed under investigation for "active corruption", the Marseille general manager was taken into psychiatric care in custody in Lille and, according to his lawyer Jean-Louis Pelletier, was a "sick fragile man, broken by the torrents of mud being thrown at him and his family".

Still Tapie was protected from the scandal, despite it slowly constricting the club, even when Valenciennes manager Boro Primorac alleged the Marseille president had offered him £66,000 to take the blame. With Valenciennes fans demanding that Marseille be stripped of their title, l'OM supporters claimed victimisation as they protested in the streets.

As Nick Bidwell wrote in The Independent on July 13: "With unemployment at 18% and the municipal finances in anaemic shape, Marseille's footballing hegemony represents one of the few sources of civic pride for a population long frustrated by the Paris-dominated centralism of the French state. To defend their football dream many have adopted a siege mentality, refusing to give credence to tales of wrongdoing and ever willing to explain the scandal as a Parisian plot to destroy Tapie and his club." Or, as one supporter simply put it in the New York Times, "France is against Marseille".

Tapie tapped into this sentiment when likening French justice officials to "the Inquisition or the Gestapo" as he complained of unfair treatment - an outburst that saw his overworked lawyers adding a libel charge to their to-do list - but still the investigation had not unearthed any evidence that...