French Wikipedia has gotten a lot better, these last few years.
Here’s a cool little article on St. Veranus (aka Veran or Vrain) defeating the Coulobre “drac”. Once again, it’s a pretty snakey dragon; and “colubra” is Latin for the female of a certain kind of snake. (The same species as the ones forming Medusa’s hair, btw.)
St. Gregory of Tours (his contemporary) tells the story in History of the Franks, but apparently things got more elaborate down the centuries.
The current story is that the female Coulobre abducted handsome young men, and the statue of St. Veran fighting the Coulobre at Fontaine-le-Vaucluse shows it with wings.
St. Veran seems to have taken the dragon to the wilderness, forbidden it to come back, and then let it go. The public works he did in the fountain area and the church he built seem to be associated with this in other legends later on, as a barrier to dragons; possibly because dragons sometimes guarded old pagan sacred springs, and Vaucluse’s fountain actually was a documented pagan sacred spring.
Anyway, much much later, Petrarch vacationed in Vaucluse and wrote a poem about Laura and the Coulobre and so forth, basically saying that for her love he could emulate St. Veran’s great deed, and build a church in the Virgin Mary’s honor just like St. Veran did. Aw. (There’s a lot of Petrarch, and I need to find the actual quote instead of people just talking about it.) The contemporary bishop of Cavaillon was his friend, and he visited him in his castle there as well as living in a little house in the village; so it was logical that he’d take an interest in St. Veran.