Three persons were in critical condition. The explosion took place at a carnival in Villepinte — a commune in in the northeastern suburbs of Paris.
According to L'express newspaper, the blast in French Seine-Saint-Denis department is considered to be an accident and not a terrorist attack.
The incident occurred when a scarecrow made of wood and straw was to be set on fire.
Some 30 people asked for medical assistance, according to Le Parisien newspaper.
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