Tens of thousands of people are taking to the streets in repeated protests, many for the first time in their lives. They are organizing assemblies and social-media campaigns even as some angry newcomers run against incumbents on the right whom they consider not socially conservative enough.

A show of strength on French streets in February led Hollande to backtrack on a measure that opponents feared could have helped same-sex couples have children through in vitro fertilization and surrogacy.

Scores of social conservatives took their children out of public schools for one day in January to protest new lessons being tested in some French schools aimed at dispelling gender stereotypes. The social conservatives said the lessons could lead to boys wearing dresses and girls playing mechanic, or even masturbation classes for children.

“We are witnessing the rise of a tea party of the French,” Valls warned in the newspaper Journal du Dimanche.

A continent already hit by economic upheaval is confronting a wave of bitter societal polarization over a host of issues such as euthanasia, abortion and same-sex marriage.