Apple has slammed France's decision to force manufacturers to make their digital rights management systems interoperable.

In a statement given to Reuters, the company condemned the decision as "state-sponsored piracy", Apple spokeswoman Natalie Kerris said.

Kerris warned that if the law passes through the French Senate (its last step before ratification): "Legal music sales will plummet just when legitimate alternatives to piracy are winning over customers."

The law demands that online music retailers furnish digital rights management tools to convert songs between different formats so that tracks from any service will play on any device. All manufacturers and music services will be affected.

Kerris said: "iPod sales will likely increase as users freely upload their iPods with 'interoperable' music which cannot be adequately protected. Free movies for iPods should not be far behind."

Meanwhile, the French government has begun a diplomatic push to have its proposals adopted across the European Union.