Calculated in accordance with International Labour Organization standards, INSEE estimated that 2.8 million people were unemployed in mainland France.
Including France's overseas territories, the jobless rate is 10.3 percent.
The unemployment rate among youths aged 15 to 24 jumped by 1.4 points over the quarter to 24.2 percent, while the rate among those over 50 edged up by 0.1 percent to 6.9 percent.
The steady rise in joblessness over the past five quarters has taken the unemployment rate to its highest since the third quarter of 1999.
Using another calculation method INSEE found that in the third quarter 3.6 million people in mainland France wanted to work including those who were not
actively looking for a job or were temporarily unavailable.
According to labour ministry data some 3.1 million people were registered to receive unemployment benefits in October.