Veteran French wing announces retirement
"I've decided to end my career. I've lived my childhood dream. It's time," the 36-year-old wrote on Twitter.
Toulon are fourth in the French Top 14 and likely to qualify for the title playoffs with the player adding: "I want to go and hunt for one more title."
Clerc scored a record-equalling 100th Top 14 try on March 10 and in 67 games for France he scored 34 tries, second only to Serge Blanco (38).
He was on France teams that completed the Six Nations Grand Slam in 2004 and 2010 and won the title in 2007. He played in the final of the 2011 World Cup, when France lost 7-8 to New Zealand.
Clerc was with Toulouse for 14 seasons, appearing in five European Cups finals and winning the Top 14 title three times.
His first season at Toulon ended when he ruptured an ankle tendon last January.
"A year ago almost to the day, I thought everything was over, as a result of my Achilles' tendon injury.
"I was planning to stop altogether, but deep inside I had the impression that the story was not finished, that there was still a chapter to write," Clerc said in a video message.