The breach was the sportsman’s photographic session for a French fashion house which came to light last week.

According to the IOC’s regulations, Olympic sportsmen have no right to participate in commercial projects unassociated with the Olympic Games between the 18th of July and the 15th of August.

Various punishments are stipulated for a violation of this regulation, from fines to losing the awarded medals.

Phelps won one of his gold medals in a 100m butterfly race, defeating Russian Yevgeny Korotyshkin with a minimum advantage.

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