The Senate adopted the bill by 196 votes to 146 on Tuesday evening. It must now be passed by the National Assembly, before becoming law.
Organisers of such pageants may face a jail term of up to two years and a fine of 30,000 euros (£25,000; $40,000).
The measure was prompted by a row over a photo shoot in Vogue magazine.
The photos published in December 2010 showed a girl of 10 with two others, all three in heavy make-up and wearing tight dresses, high heels and expensive jewelry.