Key questions and trends for Chantilly's dress rehearsal
Scott Burton on what the super Sunday card might reveal
The traditional trials card three weeks before the Qatar Prix de l’Arc de Triomphe has long been established as the key springboard to Europe's richest race.
Sixteen of the last 30 Arc winners had their prep run in one of the three races over the same mile-and-a-half course and distance.
So which horses could advance their claims on Sunday and what are the signs to look for?
Can the change in the weight-for-age scale boost the fortunes of the Prix Foy?
This is a race with a fairly dismal record for sourcing the winner of the Arc, with Daniel Wildenstein’s Allez France (1974) and Sagace (1984) the only two to complete the double, while Subotica bounced back from a defeat to win on the day that mattered most in 1992.
That is not to say other Foy winners have not gone close on the big day, with Japan's Orfevre twice finishing runner-up after taking the trial in recent years, a feat matched by compatriot El Condor Pasa behind the great Montjeu back in 1999.
It is another Japanese challenger, Satono Diamond, who will command attention on Sunday, although he faces a tough task with Group 1 winners Cloth Of Stars and Silverwave among the opposition.
Germany also fields its most plausible Arc candidate in Dschingis Secret, with connections showing they mean business by choosing the Foy over last Sunday’s Grosser Preis von Baden.
The older horse division may stage a revival, with this being the first year of the 1lb reduction in the weight-for-age allowance granted to three-year-olds.
Can Cracksman prove himself a major Arc player in the Niel?
In many of the historical examples cited, it was the late-maturing French three-year-old who played the pantomime villain, with horses like the Andre Fabre-trained trio of Carnegie (1994), Sagamix (1998) and Rail Link (2006) all having emerged in the second half of the season via the Prix Niel.
But what if this year’s destroyer of reputations is not only trained in Britain but in the very same yard as Enable?
Cracksman ran well in defeat in both the Epsom and Curragh Derbys without convincing that he was yet the finished article but a six-length demolition of Venice Beach at York spoke of a colt who is growing up fast.
To return to the original model, Fabre fields the rapidly improving Finche, who like Cracksman could prove a fine advert for his sire Frankel.
Prix Vermeille: the trial par excellence in recent years
If the Niel was the Arc trial with the best record in the 1980s and 1990s, then the Vermeille has enjoyed a purple patch in the nine seasons since Zarkava waltzed by her opposition.
While Treve is the only filly to complete the double in the interim, Criquette Head-Maarek's champion also used the race en route to the defence of her title in 2014, bouncing back from a disappointing fourth place in the Vermeille.
That completed a hat-trick for the race as a trial, with Solemia having finished third in 2012 before going on to cause the biggest shock in the last 25 years of Arc history.
The 2017 edition features no horse trading at less than 66-1, which suggests that it will take a really impressive performance from Sunday's winner to make a dent in the upper echelons of the market.
But recent precedent suggests that both layers and punters should pay close attention to the result.
Is defeat on trials day the end of the road?
We began by citing the 16 horses who have won the Arc in the last 30 years having had their previous start in one of these three traditional prep races.
Of those 16, five went into the Arc without a '1' next to their name.
Beaten triallists to win the Arc in the last 25 years
2014 Treve 4th Prix Vermeille
2012 Solemia 3rd Prix Vermeille
2004 Bago 3rd Prix Niel
1997 Peintre Celebre 2nd Prix Niel
1992 Subotica 2nd Prix Foy