The man is not believed to be affiliated with the school, which teaches grades from nursery school to high school, the British newspaper The Independent reported.
The man used a sawed-off shotgun to kill himself in the presence of a dozen students and one adult who were leaving the school for lunch, police said.
No one else was injured in the shooting.
The students attended the La Rochefoucauld school in the city's seventh district near the Invalides Monument in central Paris.
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