The Union Fédérale des Consommateurs-Que Choisir claimed it would take legal action against the two companies after conducting interoperability tests of a selection of download services.
The group claimed that, because the DRM (Digital Rights Management) systems used by both Apple and Sony restrict songs sold on their download services to being played back on their own portable players, both were guilty of anticompetitive behaviour.
Although the consumer organization has previously complained that Microsofts Windows Media system is similarly restrictive, it has chosen not to take legal action against the Redmond, Wash.-based software giant.
In a statement, the group claimed that, "The total absence of interoperability between DRM removes not only consumers power to independently choose their purchase and where they buy it from but also constitutes a significant restraint on the free circulation of creative works."
Neither Apple nor Sony responded immediately to requests for comment on the suit.
The suit, which was filed against Sony France and Sony UK, as well as Apple France and the European Apple iTunes Music Store, will be heard in the Court of First Instance in Paris later this year. UFC-Que Choisirs case is the third time in the past year that Apple has been troubled by legal action over its music services in Europe.
In November, the French Competition Council dismissed a case brought by VirginMega, the download site owned by Virgins French subsidiary, over what it alleged was abuse by Apple of the dominant market position of the iPod.
The Competition Council found that Apples refusal to open up its FairPlay DRM system to competing online stores did not amount to an abuse of its market position, although it noted that a lack of interoperability between players meant "a disadvantage for consumers."
More serious is an outstanding complaint made by U.K. consumer advocacy group Which? (formerly known as the Consumers Association) over differential pricing between European iTunes stores, which has been referred by the governments Office of Fair Trading to the EC (European Commission.)
European law means it is illegal to charge higher prices in different member states without good reason, and—should the EC find Apple guilty of a violation of this law—it could require the company to change its pricing structure, as well as levying a fine against it.
The EC has yet to give any indication of when it will decide if it will investigate the claim further. However, Apple has claimed its pricing is a reflection of the different licensing and economic structures in the music industry in each country. In a statement, the company said, "The underlying economic model in each country has an impact on how we price our track downloads. Thats not unusual: look at the price of CDs in the United States versus the United Kingdom. We believe the real comparison to be made is with the price of other track downloads in the U.K."