Tens of thousands of protesters were expected in Paris and Lyon, with smaller marches in other towns, to back the Manif pour tous's opposition to the legalisation of medically assisted procreation (MAP) and surrogate motherhood and demand the withdrawal of a pilot scheme promoting gender equality in schools.
After clashes with police during last Sunday's right-wing Day of Rage, Interior Minister Manuel Valls mobilised 1,500 police in Paris alone, ordering them to "tolerate no disorder".
"The instructions are very clear," Valls said on Saturday. "We will not tolerate any disorder or questioning of the police's integrity."
He criticised the march's organisers for failing to "reject" far-right groups whose members have clashed with police after previous demonstrations.
Last week 19 police officers were injured and 226 people arrested.
On Saturday a court overruled an order to send bailiffs to the demonstration as official witnesses at the request of the organisers who feared "numerous, random arrests ... of honest citizens".
Paris police officials said that officers were "furious" at the implied criticism of the way they work.
Along with various right-wing groups and Catholic fundamentalists, the protest organisers claim that the government is bent on destroying traditional family values under the influence of a "gay lobby".
Although ministers insist that a planned family law will not authorise MAP and surrogate motherhood, their opponents are taking pre-emptive protest action in case the Socialists try to slip the measures through before the end of Hollande's mandate.
The protest is to "warn the government as soon as possible of our opposition to the opening of MAP to female couples and gestational surrogacy because all children need a father and a mother", explained Manif pour tous president Ludovine la Rochère, recycling one of the slogans that rallied tens of thousands during the unsuccessful campaign against same-sex marriage.
The organisers have also latched onto the campaign against the government's ABCD of Equality, a pilot scheme in some schools aimed at combating gender stereotypes and promoting equality between the sexes.
Hundreds of parents are reported to have withdrawn their children from school last week due to inaccurate decriptions of the programme's content, including claims that sex toys were used and masturbation was taught, and the suggestion that it propounded "gender theory", a non-existent discipline that is supposed to claim that gender is socially constructed.
"Hands of our gender stereotypes!" reads one of the Manif pour tous's posters, which features a small boy holding a sword and a little girl dressed as a fairy.
La Rochère on Saturday demanded that the ABCD of Equality be immediately scrapped, adding that the government "has no business getting involved as such intimate subjects as sexual identity and imposing adults' concerns on children".
Although anti-gay marriage campaigners failed to keep up the momentum of their demonstrations once the law was passed, 2014 has begun with a demonstration against easing abortion law, the Day of Anger and Sunday's family-values mobilisation.
Far-right groups, Islamists and renegades from the left have joined the throng, "the only thing holding them together being their hatred of Hollande and the government's reforms", according to Robert Badinter, the lawyer and university professor credited with ending the death penalty in France in 1981.
"The more incredible the story you're spreading, the more likely it is to be believed," Badinter told Le Parisien newspaper, adding that the internet and social networkds allow rumours to reach a "considerable public".
Valls on Sunday claimed that a French version of the US's Tea Party movement was emerging and called on the mainstream right to dissociate itself from it.
The anti-government protests are a revolt of the antis, he said, "anti-élite, anti-state, anti-taxes, anti-parliament, anti-journalist ... but also and above all anti-Semites, racists, homophobes ... put simply, anti-republican".
Apart from their heterogeneous nature, the protests are remarkable for mobilising tens of thousands without the declared support of the mainstream right or even the far-right Front National, currently engaged in an effort to clean up its image.
Parts of the Catholic church have been involved, as have fundamentalist groups like Civitas, but, as in most modern protests worldwide, the main means of organisation has been the internet, especially social networks, whose lack of accountability allow exaggerations, distortions and downright lies to become undisputed truths to those who wish to believe them.
Badinter notwithstanding, the protesters are united by conservatism in one form or another, opposition to changes in social attitudes, fear of globalisation, whose most visible effects, apart from the collapse of whole industries, are immigration and multiculturalism, rejection of social solidarity.
And then there's a tendency on the French right to think that power is their natural due.
"Whenever the left is in power in France ... there is exasperation among the conservative electorate," comments Eddy Fougier of the Iris thinktank.
After the election of Socialist François Mitterrand to the presidency in 1981 the right mobilised massive demonstrations in defence of religious schools, forcing the government to back down on plans to abolish private education.
And in the 1930s fascist and royalist groups mobilised hundreds of thousands in a protest that nearly culminated in the storming of parliament, leading to a left-wing backlash that brought Léon Blum's Popular Front government to power.
Eager to put the right on the defensive, Valls and other Socialists have compared today's atmosphere to that of the 1930s, although nobody's tried to take the National Assembly by storm yet.
"This is a country that replays the French revolution every time the government changes," comments Fougier.