France were crowned A1 Grand Prix champions as Mexico won both the sprint and feature races at the Mazda Raceway Laguna Seca in California.
Nicolas Lapierre was second in the sprint race behind Salvador Duran to secure the first A1 Grand Prix series title for France.
"The team has been brilliant," Lapierre told A1 Grand Prix official website. "We have had a great season, with 13 wins and winning the series two races early."
Lapierre was leading the feature race when technical problems forced him to retire.
That allowed Mexico to became only the third team to win a double header over an A1 Grand Prix weekend.
Ralph Firman was fifth in the sprint race and sixth in the feature race. Ireland are currently eighth in the overall standings.
Robbie Kerr took fourth place in the sprint race and third in the feature race to strengthen Britain's hold on third place in the championship, behind Switzerland.
Championship standings:
1 France 163pts, 2 Switzerland 121, 3 Great Britain 88, 4 Brazil 70, 5 Netherlands 69, 6 New Zealand 67, 7 Portugal 66, 8 Ireland 61, 9 Canada 55, 10 Malaysia 54, 11 Mexico 48, 12 Italy 44, 13 Australia 41, 13 Czech Republic 41, 15 Germany 38, 16 USA 22, 17 South Africa 20, 18 Austria 14, 19 Indonesia 10, 20 Japan 8, 21 China 6, 22 Pakistan 4.
