Koller signs for Cannes
"He preferred a peaceful life with his family despite offers from German and Chinese clubs," agent Pavel Paska said.
Koller, 36, was also targetted by German Bundesliga club Hamburg.
The top scorer in the history of the Czech national team with 55 goals in 91 matches, Koller played for Monaco from 2006 to 2008 and owns a home in the Principality along the coast from Cannes.
"At 36 years, I no longer have big ambitions, I want to play football for fun," said the 2.02m striker.
He started his career at Sparta Prague, also playing for Belgian sides Lokeren and Anderlecht and German clubs Borussia Dortmund and Nuremberg.