Apple has been fined and banned from requiring staff at seven of its French stores to work night shifts.
The ruling may cause problems for arrival of the new iPad, expected next month, as staff often work after hours to reorganise the stores so that the latest merchandise is on display for product launches.
The courts took action after a group of trade unions filed a complaint. Apple was ordered to pay them €10,000 (£8,600) in damages and was warned it would be liable for a €50,000 penalty for every further infraction.
French law forbids shifts between 9pm and 6am unless the work plays an important role in the economy or, as with the emergency services, is socially useful.
Unions had complained that although Apple's stores shut at 9pm, staff were often required to stay as late as 11pm, tidying the store after hours or on duty in the workshops. Apple declined to comment.
The ruling was described as a "severe condemnation" by Eric Scherrer of the cross sector union Confédération Française des Travailleurs Chrétiens. He added: "This decision is very good and shows the court's willingness to enforce night working laws."
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