Giroud's fine effort from Franck Ribery's centre after he had been on the pitch a matter of minutes denied the Spanish a 25th successive win in major championship qualifiers but was no more than France deserved after a gritty second-half display.
Striker Karim Benzema had said he and his team-mates would be 11 warriors on the pitch and Didier Deschamps's side put a poor first-half performance behind them in which they were chasing the ball for long periods to rattle the Spanish and deny their playmakers time and space.
Sergio Ramos had put Spain ahead in the 25th minute before France goalkeeper Hugo Lloris saved a weakly-struck Cesc Fabregas penalty shortly before the break.
France looked a different side in the second half and Spain were unusually ragged, the visitors almost equalising several times before Giroud leaped to nod the ball into the corner of the net in the fourth minute of added time.
There was only enough time for Spain to kick off again before the referee blew the final whistle to prompt wild celebrations from Deschamps and his men and whistling and booing from the home support.
"After all the work we put in for 90 minutes against such a tough team you are left looking a bit foolish when you concede a draw having the three points practically in the bag," Ramos told Spanish television.
"The goal was more our mistake than any merit of France's but you shouldn't blame anyone," added the Real Madrid centre-back.
"We also had our chances, especially in the first half, to kill the game and we did not know how to.
"I am happy with the goal but it doesn't mean much if you don't get the three points."
COMPLETE CONTROL
Vicente del Bosque's all-conquering Spain side looked in complete control when Ramos put them ahead after fine work from Pedro.
It was Pedro, who scored a hat-trick against Belarus on Friday, who won the penalty when he was felled by Laurent Koscielny but Fabregas sent his kick to Lloris's right at a comfortable height.
After David Silva had been forced off injured in the 13th minute, Del Bosque's plans were further disrupted when Alvaro Arbeloa limped off five minutes after the break.
Arbeloa's replacement Juanfran did not do his chances of winning a regular starting place any good when he surrendered possession and allowed France to mount the attack that led to the equaliser.
"They pressured us a lot in the second half and we gave them too much space," Del Bosque told Spanish TV.
"But that's not to take anything away from them getting the draw," he added.
Spain, who play away in France at the end of March, remain top of the group, level with the French on seven points from three matches but ahead on goal difference.
It was only their fifth draw in their last 52 competitive matches at home, with one defeat by Greece in Zaragoza in June 2003, while Casillas missed the chance to become the first Spain goalkeeper to feature in 10 consecutive games without conceding.
