Gallas' ended his 19-year career with Perth Glory in the A-League, having spent the bulk of his playing time in England.
Starting out as a professional in his native France with Caen - where he won Ligue 2 - Gallas then had four years at Marseille before he was brought to the Premier League by then-Chelsea manager Claudio Ranieri in 2001.
Gallas won two top-flight titles at Stamford Bridge as well as the League Cup before leaving for spells at London rivals Arsenal and Tottenham.
In 2013, Gallas joined Perth, where he made 15 appearances, scoring once.
"It is not an easy thing to announce," he told L'Equipe.
"You always tell yourself that you can keep going, but, I think today I cannot go on any longer."
At the age of 25, Gallas made his France debut in a 5-0 win over Slovenia in 2002 and went on to make 83 further appearances for the national side - scoring five times.
Gallas featured in the World Cup final of 2006 as France lost on penalties to Italy in Berlin. He won the Confederations Cup on home soil in 2003 - playing in the final as France beat Cameroon 1-0 after extra time at the Stade de France.
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