Mustafa Tlass left for France for what he described as medical treatment .
Mustafa Tlass and his son , Firas , both left Syria after the revolt against Assad began in 2011 .
Mustafa Tlass left for France for what Mustafa Tlass described as medical treatment .
Mustafa Tlass and his son , Firas , both left Syria after the revolt against Assad began in 2011 .