What does Victor Hugo mean by "the red ant heaps of Toulon"?

Question

In his novel "The Last Day of a Condemned Man", Victor Hugo writes the following sequence in reference to poor people who turn to crime out of hunger:

Unfortunate beings, whom, by means of a school and a workshop, you might have rendered good, moral, useful; and with whom you now know not what to do; flinging them away like a useless burthen, sometimes into the red ant heaps of Toulon, sometimes into the silent cemetery of Clamart; cutting off life after taking away liberty.

I get that "flinging them away [...] into the silent cemetery of Clamart" means to execute them, but what does it mean to fling someone away "into the red ant heaps of Toulon"?

Answer 1

By “the red ant heaps of Toulon”, Hugo means the Bagne de Toulon, a notorious prison where the convicts wore red jackets and red caps. This is the prison where Jean Valjean serves nineteen years for stealing a loaf of bread, in Hugo’s Les Misérables.

L’habillement du forçat qui est différent pour chaque bagne, se compose à Toulon, dit l’auteur, d’une casaque de moui† rouge, dont la durée est fixée à deux ans, d’un pantalon de drap jaune, fendu de chaque côté dans la longueur des jambes, de manière à laisser passer la chaîne et pouvoir la vérifier. […]

Le forçat reçoit aussi deux chemises de toile grossière et un bonnet en drap rouge ou vert, selon que la durée de la condamnation est à temps ou à perpétuité.

The clothing of the convict, which is different for each prison, consists at Toulon, according to the author, of a jacket of coarse red cloth, which is required to last for two years, and of trousers of yellow cloth, which are split on each side along the whole leg, to allow them to pass the chain, and so that it can be checked.

The convict is also given two coarse linen shirts and a cap in red or green cloth, depending on whether the sentence is to a stretch of time or for life.

_{Pierre Zaccone (1877). Histoire des bagnes depuis leur création jusqu’à nos jours, p. 536.}

_{† I couldn’t find this term in any of the French dictionaries I checked, but it seems to be jargon for the poor-quality cloth making up the prison uniform. “Les condamnées à temps portent bonnet et casaque rouges avec pantalon jaune: le tout en une grossière étoffe nommée moui.” (Amable Tastu, Voyage en France, p. 393.)}

Answer 2

I just figured out the answer to my own question. By the "Red ant heaps of Toulon", Hugo most likely means the Bagne of Toulon, the prison that is also prominently featured in "Les Misérables" as the place in which the protagonist Jean Valjean is imprisoned for many years. It was, by modern definition, more of a forced labor camp than a modern prison, and thus the term "ant heaps" makes a lot of sense. So "flinging them away [...] into the red ant heaps of Toulon" means "subjecting them to forced labor in a prison."