Real Sociedad cannot match Paris St-Germain for glitz and glamour but the French giants may well look at their Basque visitors on Wednesday and see a blueprint for the future.

Wednesday's last-16 first-leg meeting is another step on PSG's bid for European success, something the club have craved for almost as long as they have witnessed young, talented Parisians slip through their grasp.

Kingsley Coman is the most obvious. Once the club's youngest-ever player before being released to Juventus, he scored the winner as PSG lost their only Champions League final to Bayern Munich in 2020.

Other notable names formerly on PSG's books include Chelsea forward Christopher Nkunku, AC Milan goalkeeper Mike Maignan, Real Madrid left-back Ferland Mendy, Aston Villa winger Moussa Diaby and Juventus' Timothy Weah.

That is despite Paris' local league system, the Ligue de Paris Ile-de-France, boasting more players than the population of San Sebastian, where La Real are based.

PSG owner Nasser Al-Khelaifi says the "flashy, bling-bling" era at PSG is over - and if that is true, he could do worse than look at how the club's last-16 opponents have become one of Europe's top producers of talent.

Data from Transfermarkt shows Real Sociedad have the most academy graduates of clubs left in the Champions League

When Laurent Bonadei joined PSG as a youth coach in 2012, he was convinced the club would win the Champions League within a decade.

Not only that, having observed PSG's dominance in youth tournaments all over the world, he believed they could do it with a side mostly made up of homegrown players.

"I liked what Athletic Bilbao was doing with Basque players, and in Paris, I only had Parisians," he told FootMercato

. "I told myself that we had the means to do something exceptional."

Yves Gergaud, a PSG youth coach between 2002 and 2007, was the one who scouted Coman at the age of nine but believes the lack of an established pathway has stopped such a feat coming to fruition.

"You have the academy in one corner, and the pro team in another corner, directors and managers changing all the time, so it's very difficult to really develop players," he explained in BBC World Service's documentary on Parisian talent.

"But it's true that you could field three or four teams of players from the Paris region in the Champions League."

The CIES Football Observatory calculated 42.1% of Real Sociedad minutes were played by academy graduates in the first half of the season

PSG have won nine Ligue 1 titles since Qatar Sports Investments took over in 2011 but, with European success eluding the club, they have also appointed seven managers in that time - four of those in the past four years.

That is in contrast to La Real, where Imanol Alguacil is approaching six years in charge having previously coached the reserve and youth teams, providing both stability and success by winning the Covid-delayed Copa del Rey in 2021.

"It was only a few years ago the club were having some very difficult years," Mikel Oyarzabal, one of the Zubieta academy's most-prized assets, told BBC Sport last season.

"It is a process. The beautiful things are being seen now but it was all to do with the work done years ago."

La Real's reliance on homegrown stars is born both from financial necessity and a long-standing philosophy dictated by more than 14,000 members, the club's 'socios'. According to Transfermarkt, they have built the third-most valuable squad in La Liga, behind Real Madrid and Barcelona.

Around 80% of youngsters at Zubieta come from the local Gipuzkoa region, with the occasional special talent invited from elsewhere. Antoine Griezmann was one of those, meaning the La Liga side produced more of France's World Cup-winning starting XI than PSG (0).

La Real also only dip into the transfer market to complement what they already have - currently that includes Japan star Takefusa Kubo, while David Silva and Alexander Isak have previously represented the club.

In the first half of this campaign, data from CIES Football Observatory

shows club-trained players played 42.1% of La Real's minutes, opposed to 6.5% at PSG.

And lack of opportunity is not a new issue for PSG youngsters, with high-profile signings such as Neymar and Lionel Messi traditionally favoured over academy talent.

PSG have also seen prospects enticed to other leagues, notably the Bundesliga, with former sporting director Leonardo complaining some expect to find "paradise" elsewhere.

The Greater Paris region is such a densely populated talent pool that more players at the 2022 World Cup were born there than in London and Sao Paulo combined.

It means many prospects from the region never make it to the PSG Academy at all, with other clubs in France and beyond keen to pounce.

For example, despite being born less than a 40-minute drive from the Parc des Princes, Arsenal defender William Saliba attended the academy at Saint-Etienne, 300 miles south, while Paris-born Liverpool centre-back Ibrahima Konate joined Sochaux and Barcelona's Jules Kounde went to Bordeaux.

It is not a new phenomenon, Paul Pogba and Anthony Martial were other potential stars who left Paris, but now PSG are using their financial muscle to reverse the trend.

Alongside Kylian Mbappe, who came through France's famed Clairefontaine academy before joining Monaco, PSG have signed Parisians Randal Kolo Muani and Nordi Mukiele in recent seasons, with further French additions in Ousmane Dembele, Lucas Hernandez and Bradley Barcola.

"The fans are loving the squad we have at the moment and the balance of it and the number of French players," said PSG's chief revenue officer Marc Armstrong.

Armstrong points to PSG's new training centre providing a base for all the club's teams and a change in sporting strategy that brings the first team and academy closer together.

"We have Warren Zaire-Emery, who is one of the most exciting players in Europe if not the world at the moment," he added. "We want a lot more of those players coming through in the future."

If PSG are to look closely at La Real, the key takeaway is "patience".

"There are many places where people are spending far too much money on processes we break up ourselves," explained Real Sociedad sporting director Roberto Olabe.

"Patience has to do with your commitment and your responsibility with regard to having development programmes for young players and training them based on professional ethics and to deal with the world of professional football.

"A football player needs time."