PARIS—Child beauty pageants may soon be banned in France, after a surprise vote in the French Senate that rattled the pageant industry and raised questions about how the French relate to girls’ sexuality. Such contests, and the made-up, dolled-up beauty queens they produce, have the power to both fascinate and repulse, and have drawn criticism in several countries. France, with its controlling traditions, appears to be out front in pushing an outright ban. French legislators stopped short of approving a measure banning anyone under 16 from modeling products meant for grown-ups—a sensitive subject in a country renowned for its fashion and cosmetics industries, and about to host Paris Fashion Week. The proposed children’s pageant amendment sprouted from a debate on a women’...