Talented filly Zarkava remains a warm 7-4 favourite to become the first of her sex to win the Prix de l'Arc de Triomphe since Urban Sea in 1993.

Tomorrow's event at Longchamp, in Paris, has a new sponsor and with prize money of four million euros the Arc is now the world's richest race on turf.

Zarkava, trained by Alain de Royer-Dupre for the Aga Khan, is unbeaten in her six races to date and underlined her prospects with a thrilling performance in last month's Prix Vermeille over the course and distance.

However, English trainer Mick Channon, the former soccer international who saddles last year's unlucky runner-up Youmzain (12-1), is happy to take on the filly.

Zarkava, in the biggest race of her career, will be taking on colts for the first time and dwelt badly in the stalls in the Vermeille before storming home up the straight.

Channon, recovering from an horrific car crash in August that claimed the life of a close friend, told reporters it promised to be one of the closest Arcs in a decade.

"It looks as competitive an Arc as there has been in the last 10-12 years. It's so difficult to count anything out and that's what makes it such an exciting race to look forward to."

Irish training maestro Aidan O'Brien carries two big guns.

Duke of Marmalade (7-2 second favourite) is bidding for an incredible sixth Group One race in succession. Irish Derby and Epsom Coronation Cup winner Soldier of Fortune (9-2), fifth in last year's Arc to stable companion Dylan Thomas, also holds sound credentials.

Papal Bull (25-1) and Ask (33-1), representing top Newmarket trainer Michael Stoute, are interesting outsiders.

The Arc is the highlight of a two-day $10 million festival starting today and featuring seven Group One races.