The protesters were out to back the Manif pour tous, a group that opposes the legalization of medically assisted procreation and surrogate motherhood, and calls for the withdrawal of a pilot scheme promoting gender equality in schools, Radio France Internationale reported.
In response to the gatherings, Interior Minister Manuel Valls sent out 1,500 police in Paris alone to avoid the violent clashes seen in last week's right-wing protest. Nineteen officers were injured and 226 people arrested in last week's demonstration.
"The instructions are very clear," Valls said Saturday. "We will not tolerate any disorder or questioning of the police's integrity."
Protesters accuse the government of destroying traditional family values under influence of the so-called "gay lobby."