Who was the youngest french president before macron?

Napoleon III

Explanation:

Louis-Napoléon Bonaparte, the nephew of Napoleon, was 40 when he was elected President of France in 1848.

its main object was the establishment of "settlement houses" in poor urban areas, in which volunteer middle-class "settlement workers" would live, hoping to share knowledge and culture with, and alleviate the poverty of, their low-income neighbors.