While the Prix de l'Arc de Triomphe (G1) is the main event Oct. 4 at ParisLongchamp Racecourse, there are five other group 1 races on the card, all Breeders' Cup Challenge Series: Win and You're In events. The first group 1 on the card is the Prix Marcel Boussac, a 1-mile event for 2-year-old fillies.
A proven ability at a mile has been a good pointer to success in the Prix Marcel Boussac, with six of the last eight winners having won or placed at the trip beforehand.
That statistic, coupled with the fact that seven of the last eight winners have been drawn in stall 6 or lower, suggests it may be worth taking on likely favorite Green Empress (stall 10), although she and Miss Miniver (stall 11) could well improve for the longer distance.
The one who catches the eye is Allela (stall 6), who won comfortably by 4 lengths on her debut over a mile in August at Deauville Racecourse and looked to have loads more in hand than the half-length winning margin suggests in the Prix des Aigles last time, when she quickened well to lead late on having had to wait for a gap.
She is closely related to the smart Phineas, who has six wins and a peak Racing Post Rating of 121. She has also been supplemented for this, and could well take the rise in class in her stride.
"She is a really nice filly who has shown two very different facets in her two races so far, and we don't yet know her limits," trainer Christophe Ferland said of Allela. "She had the race won a long way out on debut whereas next time she was closed in almost the whole way up the straight and in 100 meters she produced an enormous turn of foot. I'm very excited to see her run."
The Prix Marcel Boussac is Breeders' Cup Challenge Series race for the Breeders' Cup Juvenile Fillies Turf (G1T), granting the winner an automatic, fees-paid berth to that Oct. 30 race at Keeneland.
Prix Jean-Luc Lagardere
Aidan O'Brien has become synonymous with multiple runners in group 1s and he sends three into battle in Prix Jean-Luc Lagardere (G1), but that is not typical for this race.
In the last 10 years O'Brien has saddled only 11 runners in the 7-furlong group 1 for 2-year-olds, so an average of just over one each year, and his record is strong given that small sample. He won it with Happily in 2017, Camille Pissarro in 2024, and Puerto Rico last year. He also saddled Unquestionable to finish second in 2023 and had Armory take third back in 2019.
O'Brien appears to be desperate to complete the hat trick this year and all three of his runners—Man's Best Friend, Aix La Chapelle, and Florida Bay—are big prices, even the Ryan Moore-ridden Man's Best Friend is verging on double figures going up against Joseph O'Brien's Folsom Blues, winner of the Vincent O'Brien National Stakes (G1) last out.
"Ryan rode Man's Best Friend at Deauville last time and the first thing he said when he came in was to go up to 7 with him," Aidan O'Brien said. "He's not slow and he won the Richmond, so it'll be interesting to see what will happen.
"Florida Bay is a very tough and solid horse who we think will love the track. Aix La Chapelle hasn't run in a while, so we need to get a bit more experience into him. He might need another furlong in trip before you see the best of him, but he's in good form."
The winner of the Jean-Luc Lagardere will earn a "Win and You're In" berth to the Breeders' Cup Juvenile Turf (G1T) Oct. 30 at Keeneland. The race is also part of the Euro/Mideast Road to the Kentucky Derby, awarding qualifying points on a 10-5-3-2-1 scale to the top five finishers toward the 2027 Kentucky Derby (G1).
Prix de l'Abbaye de Longchamp
Since the Arc meeting returned to ParisLongchamp Racecourse in 2018, horses drawn in the five lowest stalls in the Prix de l'Abbaye have held a 58% greater chance of winning than the average.
That is bad news for ante-post favorite Naana's Shadow, who is drawn in stall 14 of 15. It may not be as disastrous as it seems, though. Most of the paciest types in the field have been drawn away from the rail, too, meaning it is not out of the question for one to tack across.
Veteran Ponntos is in stall 1. Had he been a couple of years younger, he might have made the most of the situation. As it is, the next lowest-drawn front-runner, supplemented filly Miss Yechance, could be the likeliest beneficiary. She is seriously progressive, winning a handicap followed by a group 3 in her last two starts, and her searing pace has been a hallmark of both wins. Stall 8 is not a bad draw at all this year.
"She looks in great shape and deserves to take her chance. The owners have sportingly supplemented her and I think we've got a reasonable draw," trainer Karl Burke said. "She's got a lot of early pace and if she jumps, hits the lids quick and gets near that rail, she'll run a big race. She's looking better and stronger with each run, so I'm very happy with her."
The Abbaye winner will earn an automatic, fees-paid berth to the Oct. 31 Breeders' Cup Turf Sprint (G1T).
Prix de l'Opera
Not many Prix de l'Opera fillies and mares would be genuine Arc contenders but that case can be made for Aventure who took the scalp of Diamond Necklace in the Prix Jean Romanet (G1) when last seen. That rival is as short as 12-1 for Sunday's Arc despite a horror draw in stall 16.
There was no fluke about the Romanet success despite the Ballydoyle inmate going off at long odds-on, and Aventure has back class having finished runner-up in Bluestocking's Arc. She went on to Prix Vermeille (G1) success last term and while she subsequently struggled in 2025's Arc, that was excusable from a wide draw.
The 5-year-old looked right back to her best last time out and connections could be left wondering what could have been if they had opted for the big one 45 minutes earlier.
The winner of the 1 1/4-mile Prix de l'Opera will earn a Breeders' Cup Challenge Series berth to the Breeders' Cup Filly and Mare Turf (G1T).
Prix de la Foret
The Prix de la Foret (G1) starts at the highest point on the track at ParisLongchamp, with most of the downhill run in the early stages.
For this reason, horses with strong sprinting credentials tend to do well even though the race is run over 7 furlongs. Recent winners such as Space Blues and Kinross mixed 6 furlongs and 7 furlongs to good effect.
It may be a surprise that the Prix Maurice de Gheest (G1), over 6 1/2 furlongs at Deauville, does not have an even stronger bearing on the race. Samangan won that race in August and is progressing generally.
Samagan's trainer Francis-Henri Graffard said, "I think he's a lot stronger than in the summer and he's improved a lot. I couldn't be happier with him and I think on good ground he'll run a very big race."
There are only eight runners and Samangan is drawn in stall 7, so the main early issue could be getting cover. As long as he picks the right wheels, he has the pace to go back-to-back at group 1 level. Aidan O'Brien has last year's Prix Jean-Luc Lagardere winner Puerto Rico, who is still looking for his first win as a 3-year-old, and One Thousand Guineas (G1) winner True Love.
The winner could seek to emulate Space Blues by following up a Foret victory with a win in the Breeders' Cup Mile (G1T), to which the winner will earn an automatic, fees-paid berth.
