A battle has broken out in France between campaigners against sexual harassment and a group of prominent women who argue overzealous misconduct allegations threaten the country’s embrace of sexual freedom.

Film star Catherine Deneuve and more than 100 French women this week published a letter in the newspaper Le Monde defending the lustful advances of their male compatriots, and denouncing what they call “puritanism” of the #MeToo campaign against sexual harassment that has taken root in the U.S. and other countries since...