Official figures show that French industrial output fell unexpectedly in June, hit by declining production of food, cars and capital goods. This has heightened fears of a recession in France and added to the pile of weak euro zone data.
Output overall fell by 0.4% in the euro zone's second-biggest economy, national statistics office INSEE said. Economists had expected it to rise by the same amount.
May's headline figure was revised down to -2.9% from a previously reported -2.6%.
The French data follow Italian growth figures on Friday which showed a fall in gross domestic product of 0.3% in the second quarter. Some analysts believe this has set the stage for a contraction in the whole euro zone economy when figures are released later this week.