Soaraway temperatures are affecting large parts of France and were expected to peak at 42 degrees Celsius (107.6 degrees Fahrenheit) in the wine-growing Rhone valley.
Police are working on the assumption of mistaken identity, after the boy was shot while travelling in a car with his uncle through the deprived Pissevin area of Nîmes.
A convoy of environmental campaigners set off from rural France on Friday to protest over the construction of large-scale reservoirs they say amount to "water grabbing" by the agriculture industry.
Speaking particularly about the Crimean peninsula, which Russia claimed to have annexed in 2014, the former French leader said that "any return to the way things were before is an illusion".
The wildfire, which began Monday in the eastern Pyreneees area popular with tourists and close to the Spanish border, destroyed a campsite and forced the evacuation of more than 2,000 people before some 650 firefighters finally brought it under control on Tuesday.