According to France-based Deliverability monitoring company DeliverNow, French ISPs Orange, SFR, and Laposte.net have deployed a new spam filtering mechanism powered by Vade Retro.
This new filtering will dynamically block senders who have an elevated spam complaint rate. (I don't currently have data on what would constitute an elevated spam complaint rate in this scenario.) I am told that the fingerprinting for complaint rate calculation is based both on the sending IP address, subject line and various bits of sender identification. This strongly implies that a sender with complaint issues won't be able to bypass this filtering by sending via multiple IP addresses or via multiple email service providers.
As always, an ounce of prevention is worth a pound of cure. Ensuring you have permission before mailing recipients, ensuring you weed out unengaged recipients, and sending only expected mail will always go a long way toward making sure that your spam complaint percentages aren't any higher than those of the next sender.
(H/T: Arnaud Clément-Bollée)