The swimming leg of a triathlon test event ahead of next year's Olympic Games in Paris was cancelled on Sunday due to poor water quality in the River Seine, the third such decision this month.
"Water quality tests do not provide the necessary guarantees to properly hold the swimming event," organisers said in a statement.
The mixed relay triathlon test event was switched to a duathlon format as was the case on Saturday for the Para triathlon event.
Organisers also cancelled the Open Water Swimming World Cup in Paris this month after heavy rainfall caused the water quality in the river to dip below minimum health standards.
The city has been working on clean-up efforts to make the Seine swimmable again, as it was during the 1900 Paris Olympics.