AIDAN O'BRIEN will attempt to storm the ramparts of another European Group One prize this afternoon when Alessandro Volta leads a three-strong Irish challenge on the Juddmonte Grand Prix de Paris at Longchamp.

The €600,000 Bastille Day highlight has attracted a field of 13, including the sponsor's representative, Doctor Fremantle, who ran fourth in the Epsom Derby.

However, there will be a lot of interest in the clash of Alessandro Volta and Curtain Call, who finished fourth and fifth respectively in the Irish Derby after the O'Brien horse veered dramatically left in the straight, ruining Curtain Call's chance in the process.

That incident will be the subject of a Turf Club appeal later in the month, but Curtain Call's connections will be hoping for early revenge and have booked Frankie Dettori to ride.

John Murtagh will be on Alessandro Volta again, while Séamus Heffernan is on board Bashkirov and Colm O'Donoghue is on the third O'Brien representative, William Hogarth.

Killarney's four-day July festival opens this evening, and Spiriton looks a bet to keep punters happy, despite having topweight of 10st in the second of the 11-furlong handicaps.

The Paul Cashman-trained horse was a good winner of a Bellewstown hurdle recently and has just the third start of his career on the flat tonight. The first of them came in his native Germany in 2004, while the second last year at Galway is only encouraging because he now races off a 7lb lower mark.

Cashman's horses are in flying form and Spiriton looked to be still progressing at Bellewstown. Pat Smullen's booking only encourages too.

The Fortria winner French Accordion put in a good effort on the level at Leopardstown on his reappearance and Paul Nolan's horse is rated to land the featured chase.

Fran Berry travels north to Downpatrick, and the season's leading rider can succeed on board Wing Stealth, who was only overhauled by Old Chatham in the closing stages of her last start at Leopardstown.