Fifa's dispute resolution chamber ruled that Chelsea had been guilty of inducing Gael Kakuta to break his contract with Lens in 2007.
And Fifa has confirmed to the BBC that there is a case pending involving Helan, City and Rennes with their player status department, which deals with the registration of footballers.
Rennes technical director Pierre Dreossi told The Independent newspaper: "For us it was strange to have no discussion from City.
"And now, in the week after the declaration on Chelsea, I would hope that it will be the same thing for Manchester City."
Rennes claim Helan signed a pre-contract agreement with them as a 13-year-old that tied the player and club to a deal if the player represented France at junior level. The defender, dubbed the new Patrice Evra, went on to captain the France under-16 team.
As it stands, European law prevents players from signing formal contracts tying them to clubs before their 16th birthday meaning that the club is in danger of losing them to another team when they reach that age.
This is further complicated by the fact that different nations are governed by different rules and sporting jurisdiction is sometimes at odds with employment law.
Helan had initially been the subject of interest from Manchester United but eventually joined City - with The Independent reporting that the French Football Federation provided an International Transfer Certificate.
Droessi said this had been provided in error and added: "Manchester City must now realise the consequences of their attitude in the Helan case as it is even more illegal than Kakuta."
In addition to the cases involving Kakuta and Lens, and Helan and Rennes, another French club has made claims against a Premier League side.
Le Havre have alleged that Manchester United offered financial inducements to the family of 16-year Paul Pogba to lure the teenager to Old Trafford.
United say they will take legal action against Le Havre unless they stop making the allegations.
Ian Dennis and Brian Alexander host a BBC Radio 5 Live special on the fall-out from Chelsea's transfer ban from 1900 BST on Tuesday.
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