The jobless figure, based on the measurement criteria of the International Labour Organisation (ILO), showed the scale of the challenge President Francois Hollande faces as he seeks to make good on a goal of reversing the upward trend by the end of 2013.
Youth unemployment rose more markedly, with the jobless rate edging up to 24.9 percent, from 23.6 percent, among people under 25 years old. That was higher than any quarter on records going back to the start of 1996.
Excluding overseas territories such as the Caribbean islands of Martinique and Guadeloupe, the unemployment rate on mainland France was 9.9 percent in the third quarter, up from 9.8 percent in the preceding three-month period.
That meant the number of unemployed stood at 2.83 million in the third quarter, with the number of jobless youth, at 671,000 in mainland France, 1.4 percent higher than in the previous quarter and 2.8 percent higher than a year earlier.
On the non-ILO measure issued by the Labour Ministry, the picture is even bleaker, with October data showing mainland jobless totals at 3.1 million, the highest in 14 years.
Francois Hollande, who took over in May as France's first Socialist president in 17 years, has promised to reverse the upward trend by the end of 2013.
His government is struggling to combat a haemorrhage of jobs in industry while curbing public spending and raising taxes to help slash debt, all at a time when Europe's second largest economy has stopped growing.
While the government is under pressure from voters and from unions, France is enjoying a good run in the financial markets, where the cost of financing its debt has dropped noticeably.
The yield on French 10-year government bonds fell below 2 percent for the first time on Wednesday, benefiting from a push towards higher-rated, less-risky assets after a lacklustre Spanish auction renewed the flight to quality.
The French 10-year yield reached a record low of 1.995 percent, beating a previous record of 2.011 percent in early August, and edged marginally lower again on Thursday, to 1. 994 pe rcent at 0731 GMT, according to Tr adeweb pr ice data.