Navalny, a whistle-blowing blogger and politician who ran for mayor of Moscow against a Putin-backed establishment politician, is being investigated for allegedly defrauding French cosmetics giant Yves Rocher out of $790,000.
Judge Artur Karpov made the ruling after an investigator complaint that Navalny allegedly violated his bail terms, the state-supported RIA Novosti news agency reported.
Preventing Navalny from using the Internet would keep him from updating his widely followed Twitter account and blog, which he uses to rally anti-government supporters, RIA Novosti said.
The house arrest would be effective up to 60 days.
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