Economic expansion in the euro zone slowed to 0.4% in the third quarter, statistics agency Eurostat said on Friday.
The 21-nation euro area rebounded to 0.6% growth in the second quarter, following stagnation in the first three months of the year.
The flash third quarter reading was nonetheless higher than the 0.2% growth that was forecast in a Reuters poll of economists.
However, France's economy unexpectedly contracted by 0.1% over the July to September period. The country is grappling with soaring borrowing costs as investors balk at a political struggle to reduce its high budget deficit and mounting national debt. October has also brought growing nationwide unrest over the cost of living and other issues, which has at times escalated into violent and costly rioting.
Germany, the euro zone's largest economy, grew by just 0.2% in the third quarter. Growth in the bloc's third-biggest economy, Italy, was flat.