Do most racehorses end up on a plate in France??

no.

Special double green label

No, which is why racehorses can be given drugs that humans are not allowed to eat.

Of course the french do, cheval can be bought in most French supermarkets. In fact there was a Panorama program last year about thousands of racehorses slaughtered for meat in Ireland. Most Irish carcasses are exported to Europe, where they are eaten as burgers, steaks or roasts. If you buy a street kebab in Paris (the ones with slices of meat on the skewer) it might well have slices of cheval. Switzerland, Belgium, Germany, Poland other European countries where horse meat is eaten.

https://www.irishmirror.ie/news/irish-news/thousands-thoroughbred-horses-killed-eat-26972921

Dog food more likely surely?

Is it sold as fast food if it was a sprinter?

Not the ones I backed.

Many of us were blissfully unaware we were eating them several years ago when the horsemeat scandal broke. Leading supermarkets were selling 'tainted' meat to punters. Pays to purchase from reputable sources and avoid your cheap ready meals/burgers etc.

Some folk were happy to stirrup trouble, supermarkets saddled with the losses, some people fell ill with the trots and others abandoned meat altogether and switched to products such as uniquorn for example.

The man on the burger near me asked me at the time what I'd like on my burger.
I replied....... "£5 each-way please"

Aldi were selling Greg Chung burgers leif,not horsemeat,pulled pork!!