PARIS — The highest constitutional body in France on Wednesday defanged the government’s plan to cut off the Internet connections of digital pirates, saying the authorities had no right to do so without obtaining court approval.

The decision, by the Constitutional Council, which reviews legislation approved by Parliament before it goes into effect, is a major setback for the music and movie industries, which had praised the French law as a model solution to the problem of illegal file-sharing.

The council rejected the core portion of the measure, under which a newly created agency, acting on the recommendations of copyright owners, would have been able to order Internet service providers to shut down the accounts of copyright cheats who ignored two warnings to stop.

The council said the proposal was contrary to French constitutional principles, like the presumption of innocence and freedom of speech. The latter right “implies today, considering the development of the Internet, and its importance for the participation in democratic life and the expression of ideas and opinions, the online public’s freedom to access these communication services,” the council said.