When Laurent Blanc confirmed the end of Lyon's hegemony by leading Bordeaux to the Ligue 1 title in 2009, an era dawned in which France enjoyed the most open of all Europe's main leagues. Now Blanc must prove that brief era is over and that French football has entered a new age in which the top of the table is reserved for billionaires, meaning just two clubs – Paris Saint-Germain and the new rich kids on the block, Monaco. The past five seasons in Ligue 1 have produced five different winners but now and for the forseeable future there are only two contenders.

By chance the fixture list has ruled that the Ligue 1 season will kick off on Friday with a clash of the last two champions but PSG versus Montpellier is not a peer group meeting and, regardless of the result, it is nigh-on impossible to imagine Montpellier finishing above the club from the capital this term.

Granted, it was improbable in 2011-12 and Montpellier still won the league for the first time but the gap in resources has since grown from huge to humungous and whereas PSG have continued to strengthen, splurging £50m this summer to add Edinson Cavani to a side already featuring Zlatan Ibrahimovich, Ezequiel Lavezzi and Lucas Moura, Montpellier have lost many of the people responsible for their surprising triumph two seasons ago. The club's new manager, the veteran Jean Fernandez, reckons the best they can achieve is a top-half finish.

Most other clubs have also had to revise their forecasts downwards owing to financial constraints made tighter by tax changes and commitments to build or refurbish stadiums before the 2016 European Championship that France is hosting.

Lyon and Marseille need to sell their main strikers, Bafétimbi Gomis and André-Pierre Gignac, and replace them with youngsters or cheap recruits, which is how Saint Etienne hope to fill the void left by Borussia Dortmund's purchase of the leader of their attack, Pierre Emerick Aubameyang. Meanwhile, PSG and Monaco carry on buying.

PSG are favourites for the title because they have had a two-year headstart on Monaco, who only returned to the top flight this season after winning Ligue 2 on the back of investment by their new Russian owner, Dmitry Rybolovlev. Their manager, Claudio Ranieri, has been treated to almost a whole new team since then and Radamel Falcao, James Rodríguez, João Moutinho et al can be expected to make a big impact but it will probably still take time for Ranieri to hone his side and, despite forking out around £150m this summer, Monaco still do not have a squad as deep as PSG's.

What is more, while PSG grumbled last season that they received harsh treatment from some referees owing to jealousy of their wealth, there is more obvious official hostility towards Monaco, whose status as a tax haven has been under attack by league authorities. Monaco have been to France's highest court in a bid to overturn a decision to effectively ban them from Ligue 1 unless they subject themselves to the same fiscal regime as the other clubs but so far all they have achieved is clarification that that ruling will not take effect until next season.

A negotiated solution could be found before then but at the moment the different parties are way apart. Monaco's sense of persecution has been intensified by beginning this campaign with a two-point penalty because a referee was hit after some of their fans invaded their pitch on the final day of last season to celebrate promotion. Monaco's appeal against the penalty was due to be heard on Thursday afternoon.

PSG have the best squad but it remains to be seen whether they have the best manager or at least one capable of making sure they do not squander their massive advantage. Blanc's star has fallen since he made Bordeaux champions, largely because of France's miserable contribution to Euro 2012, where his team were too defensive on the pitch and too offensive off it. He was not high on PSG's wishlist for a new manager after Carlo Ancelotti defected to Real Madrid this summer, only getting the job after several others turned down the short-term contract on offer.

At Paris he will have to prove he can channel big egos, a task made all the more difficult by this summer's departure of Leonardo, the sporting director who signed most of the players and had been instrumental in keeping them devoted to the Parisian "project".

The fact that PSG are expected to dominate most matches and win with pizazz, while also challenging for the Champions League, also makes this a very different venture to the one he masterminded at Bordeaux. He is smart enough to evolve but has to show that he has done so fast.