In Les Misérables, Victor Hugo claims that children were kidnapped during the reign of Louis XV, and rumours were whispered of the King's 'purple baths'. What is Hugo referring to here and would the rumours have been common knowledge to a reader at the time?

For those not familiar with Hugo's work, the passage you are referring to reads as follows:

These abandonments of children, be it said, in passing, were not discouraged by the old monarchy [ie, the Bourbon Ancien Regime which ruled until the French Revolution - Hugo was writing of the early 1830s]... Moreover, the monarchy sometimes had need of children, and then it skimmed the street...

Under Louis XV, children disappeared in Paris; the police carried them off – nobody knows for what mysterious use. People whispered with affright horrible conjectures about the purple baths of the king. Barbier speaks ingenuously of these things. It sometimes happened that the officers running short of children, took some who had fathers. The fathers, in despair, rushed upon the officers. In such cases, the parlement interfered and hung – whom? The officers? No; the fathers."

Hugo is referring here to rumours that abounded during the reign of Louis XV (1715-1774) that the monarch suffered from leprosy, and his source is the lawyer Edmund Barbier's diaries, published in Paris as the Chronique de la régence et du règne de Louis XV (1718–1763) in eight volumes in 1857. According to Barbier, writing on 16 May 1750,

"For a week now people have been saying that police constables in disguise are roaming around various quarters of Paris, abducting children, boys and girls from five or six years old to ten or more, and loading them into the carriages which they have ready waiting nearby."

Barbier added that it was generally believed that these agents of the monarchy worked on behalf of

"a leprous prince whose cure required a bath in human blood, and there being no blood purer than that of children, these were seized so as to be bled from all their limbs."

Jones notes that while these rumours did not specifically identify which member of the Bourbon line was leprous, "in accounts which circulated widely at court and which reached the ears of the king himself, that leprous prince was metamorphosed into the morally and spiritually unclean and sexually debauched Louis XV", leading the king to complain that "the wicked people... are calling me a Herod."

The widespread belief of this rumour led in 1750 to serious rioting in six districts of Paris, the proximate cause of which was a police drive to sweep the streets of vagrant children. This drive had its roots in an instruction issued late in 1749 by the Lieutenant General [commander] of the Paris police, Nicolas-René Berryer (1703-62) – a protégé of Louis XV's mistress the Marquise de Pompadour, but also an innovative officer who is generally credited with both the creation of the Sûreté ["Security Office"] and a domestic espionage system based on networks of police spies.

Berryer ordered that

"all beggars and vagrants found in the streets of Paris…of whatever age or sex, shall be arrested and taken to prison, there to be detained for as long as shall be deemed necessary."

In practice, however, it proved much easier to catch children than adult vagrants, and since the Paris police were being rewarded on the basis of the number of "beggars" they could arrest, they detained a disproportionate number of youngsters - enough for the locals to assume that the round-up was being specifically directed against them. Berryer then further compounded matters by issuing another order for the detention of "all children of workers and bourgeois alike caught gambling in the squares and market places along with other little rascals and vagabonds." This guaranteed that at least some of those arrested had parents and other relatives on hand to protest the new policies – hence the outbreak of disorder.

It was widely assumed that the children caught up in this drive were not merely being relocated or imprisoned, but that they were actually being arrested in order to be supplied to the Bourbon court, and according to one police report, a spy haunting a tavern near the Place des Victoires heard a local woman claim that they would have their revenge for these atrocities: "Our women of Les Halles will go to Versailles to dethrone the King and tear his eyes out."

At least 20 people were killed during the rioting, and three of those involved were arrested and hanged for public order offences. Intriguingly, the police (apparently seeking to distract attention from their own heavy-handedness) were responsible for the unleashing of another rumour – that the riots had been provoked by mysterious "men in black" who worked their way through the crowds assembling on Paris's streets, and offered money to those willing to start trouble.

Sources

Arlette Farge & Jacques Revel, The Vanishing Children of Paris: Rumor and Politics before the French Revolution (1993)

Victor Hugo, Les Misérables

Colin Jones, The Great Nation: France from Louis XV to Napoleon (2003)

Alan Williams, The Police of Paris, 1718-1789 (1979)