Corran Ard is responding well to care.
Volunteers with the non-profit organisation discovered the racehorse while monitoring "rescue" forums in France and saw he was at risk of going for meat.
The group discovered his last run was March 26 - less than a month before his arrival on the website on April 20.
His most recent trainer, Tim Vaughan, was contacted and a series of emails ensued between the group and Vaughan's assistant, Mark Gichero.
Corran Ard came off the website, with the group receiving an email from Gichero saying that he had been in touch with his contacts in France, who had assured him the horse would be found a home through them.
"In the interim, after doing more research, we found other British ex racers on that site from the same region of the UK," group secretary Jenny Lupton said.
"We alerted the British Horseracing Authority to the fact, and they have passed the details to their investigations team.
"Imagine then, our surprise and horror when the horse re-appeared on the website on June 5, now at a lower price and in imminent danger of going to the abattoir.
"We decided there was no time to waste. To ensure that the horse was given every chance of a future, but also very much to highlight the fact that this cross-channel trade in unwanted UK horses and ponies to French dealing/meat yards is happening, we contacted the newspapers," Lupton said.
It alerted British newspapers, which in turn contacted Gichero, who was horrified that the horse had resurfaced back in the same place.
Gichero chose to fund the purchase and transport of Corran Ard, who was collected on June 28 by Equine Rescue France.
Lupton says of their new charge: "He is a beautiful, sensitive horse who was obviously shell-shocked at the immediate change in his circumstances. Going from five-star treatment in a racing yard to being on the meat trail must have been bewildering and terrifying for him."
He still had his racing plates on from his last start more than three months ago.
"He will take some careful rehabilitation. Luckily, the attention being lavished on him was quickly accepted as his due, and the spark is back in his eye. The physical recovery will, sadly, take much longer."
Corran Ard had been retired from racing because of a long-term injury. The horse was thought to have gone to a good home in southern England.