However, two of the biggest punts will not involve anyone queuing up today at the pari-mutuel windows at the elegant track by the Bois de Boulogne or a trip down to the local bookmakers. The money is already down and, in one case, has been so for some time.
It would be almost impossible to quantify just how much Japan has spent on bloodstock over the past 30 years in the quest to become a major racing nation, but pluck a figure of around $1 billion out of the air and there will be few arguments.
It started with the acquisition of potential stallions such as Sunday Silence, the 1989 Kentucky Derby and Breeders' Cup Classic winner, who would go on to be the champion sire 13 times in Japan before he died in 2002 and his influence carries on through progeny such as Orfevre, who will try to become the first Japanese-trained Arc victor.
The winner of last year's Japanese Triple Crown has already won a jaw-dropping £7.7 million in 13 career starts and will line up for one of Europe's biggest prizes against a horse whose story has more than a touch of Hollywood about it.
Saonois, who won a claimer a year ago and was still running on the all-weather track at Cagnes-sur-Mer as recently as February, was given a supplementary entry by his connections on Thursday at a cost of €100,000. That may be small change to the major owners of world racing but it is a lot of bread for a baker from the French provinces.
Pascal Treyve is living the dream with Saonois, a colt who was rejected as too small by many when he first went to the sales where he was one of three horses bought for a total of only €13,000 by trainer Jean-Pierre Gauvin.
It was not looking a good deal at first when Gauvin dropped Saonois into a claimer at Deauville last October just to get him to win a race. But since then the horse has surpassed all expectations by winning seven of his 10 starts.
Saonois has taken one of the most obvious routes to the Arc but has not always looked impressive in doing so. He was a rank outsider when he won the Prix du Jockey Club at Chantilly in June and was considered to have been fortunate to weave his way through a race that was so rough it threw up more hard-luck stories than the poorhouse.
Saonois came back last month with a win in Group Two Prix Niel on Arc Trials day at Longchamp. That was enough to prompt an inquiry from a member of the Qatari royal family as to whether the horse was for sale. Treyve, who owns Saonois in partnership with Gauvin, turned down the reputed €3 million offer and together they used some of the €1.7m the horse had already won to run in the Arc.
"I feel like I've made all the followers of Saonois happy," Treyve said last week. "I have made people dream. I have proved that it is possible, even if it remains exceptional."
Treyve, who lives in the village of Bellegarde-en-Forez in central France, had a horse with Gauvin before, Cadran, which ran in 54 races and won €140,400 in prize money. It was that success which allowed Treyve to buy his share in Saonois for €4000.
He might not want to part with his horse but Treyve is thinking of selling the bakery business, partly because his son has developed an allergy to flour. If Saonois wins the Arc, and another €2.2m, the baker will not be worrying about dough for a little while yet.
But even that figure may pale when the fans of Orfevre hit town. The Japanese have finished second in the Arc twice in recent years, with El Condor Pasa in 1999 and Nakayama Festa in 2010, but the one who made the biggest impression was Deep Impact.
In 2006, an estimated 5000 Japanese in the crowd mounted an epic gamble on their horse with €1.6m pouring into the tote to make Deep Impact one of the hottest favourites in the race's history. However, he could finish only third to Rail Link.
The same can be expected this time for Orfevre as, while Camelot, the 2000 Guineas and Derby winner who will be ridden by Frankie Dettori, got a prime draw in stall five, Orfevre is widest of all in stall 18 and no horse has won from a double-figure draw since Dalakhani from stall 14 in 2003.
Orfevre has already travelled halfway around the world but he will have to travel a little further if he is to make history.
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