PARIS -- A closely watched French law that allows regulators to force Apple Computer Inc. to make its iPod player and iTunes online store compatible with rival offerings went into effect last week.

The Internet copyright law included passed France's parliament June 30.

The Constitutional Council threw out several measures last week, concluding that they violated constitutional property protections.

French President Jacques Chirac signed it this week with the body's changes. The law was published in the government's Journal Officiel on Thursday, formally putting it into force.

Apple, which had described an earlier draft of the copyright bill as "state-sponsored piracy," did not respond to calls and messages seeking comment Thursday.

Currently, songs bought on iTunes can be played only on iPods, and an iPod can't play downloads from other stores that rival iTunes' premium music catalog -- like Napster and Sony Corp.'s Connect.

In a sign that other governments may follow France's example, recent proposals or regulatory moves to open up iTunes have emerged in Britain, Sweden, Denmark, Norway and Poland.

In France, the discarded measures softened the law, but it was not immediately clear to what degree.

The law's champion, Culture Minister Renaud Donnedieu de Vabres, expressed satisfaction at the council's ruling, insisting that it upheld the "overall balance of the text."

The law "reconciles the future of French musical creations and cinematography and that of free software, and Internet users' access to culture," he said in a statement.

But the UFC-Que Choisir consumers' group criticized the council, saying it rejected the measures most favorable to consumers. One of the abandoned measures would have lessened fines for file sharing.

The council also ruled that the law's definition of "interoperability" was too vague.

Interoperability was at the heart of the argument against exclusive formats like that behind the iPod. The original law stated that companies are expected to share the required technical data with any rival that wants to offer compatible music players and stores.

The council left it up to government regulators to set the terms for asking companies to open their formats to rivals -- in exchange for some compensation.

Much could also depend on the law's interpretation by the French courts, as well as the stance taken by recording companies.