Natroun over 2400 metres at Longchamp Racecourse on 7 May. Two weeks later he contested the Prix de l'Avre over the same course and distance and won by five lengths from Bilal. Following the race, the colt's owner paid a supplementary entry fee of approximately £15,200 to enter the horse in the Prix du Jockey-Club, reportedly at the urging of Saint-Martin. On 7 June, Natroun contested the 150th running of the Prix du Jockey-Club over 2400 metres at Chantilly Racecourse. In France, horses in the same ownership or stable are coupled for betting purposes. The Vincent O'Brien pair Ancient Times and
Prix du Moulin de Longchamp when the racecourse was built in 1856. The Prix du Moulin de Longchamp was one of two major races introduced to celebrate Longchamp's centenary in 1957. Both initially took place on the first Sunday in October, the same day as the Prix de l'Arc de Triomphe. The other race, the Prix de l'Abbaye de Longchamp, is still held at that meeting. The Prix du Moulin was moved to late September in 1974, and to the first Sunday of that month in 1980. It was formerly contested on Longchamp's middle course (the "moyenne piste"), but was switched to the main course