There has been mutual enmity between the two for many years, and the Tottenham defender believes that the Manchester City playmaker's volley of abuse revealed his true personality
The French pair have been involved in a long-running war of words since the 25-year-old allegedly refused to give up his seat for legendary striker Thierry Henry on Les Bleus' team bus at Euro 2008.
Gallas reportedly accused his compatriot of a lack of respect and the players are believed not to have spoken during their time together in north London.
And now, following Nasri's angry tirade in which he offered to fight a reporter after his side's Euro 2012 quarter-final loss, the Tottenham stopper insists observers will sympathise with his position.
"He never stopped believing that I was the worst person, and has dirtied my name. You know, I took an earful"
"People have really learned for themselves who Samir Nasri truly is. And I wasn't in Ukraine or Poland!" he told France Football.
"He never stopped believing that I was the worst person, and has dirtied my name. You know, I took an earful.
"It was always my name in the press or elsewhere, fingers were always being pointed at me, while many of the people in the world of football were aware of Nasri's character.
"There was a match with Arsenal in Rome, and a serious discussion in the changing room at the end of the match. He lost a ball, I showed my disappointment, and he called me a 'son of a w****'."
However, the 34-year-old, who missed out on a place in Laurent Blanc's squad this summer, believes others are also to blame for Nasri's attitude.
"I don't want to make excuses for the young players who have big heads, but they're not the only ones to blame," he added.
"When a youngster has talent and is coveted by big teams, his club does everything to keep him, and accepts his every whim.
"They [the players] don't have the circumspect, or enough maturity to take a step back. Everything happens too fast for them, and they no longer control the situation.
"I remember once, you used to, quite rightly, wait your turn for the France team, even if you were a talented young player. Today, the coaches give them the keys immediately."