Paris is in competition with Los Angeles to host the 2024 games. Hildalgo has repeatedly said she intends to see Olympic swimmers use the river that snakes around Notre Dame Cathedral and past the Eiffel Tower should Paris be victorious.
"This opens that door to open water swimming in Paris," Hidalgo said at the opening of the canal water pools, sectioned off and filtered in the Bassin de la Villette, a wide section of canal in the north of the city.
"Thanks to the Olympic Games we'll be able to see to it that the water in the Seine is clean water."
A Triathlon open water swim was held in the Seine in 2011, but a competition scheduled for 2012 was abandoned partly because of health worries. Casual bathing in the Paris section of the Seine was outlawed in 1923 and swimmers are a rare sight, even on the hottest days of the year.
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When he was mayor of Paris in 1990, former French president Jacques Chirac pledged to make the Seine clean again and said he would swim in the river himself in three years time.
There is no record that he kept that promise, but progress has been made. Some species of fish absent for decades are now back, and Celia Blauel, a Paris city environment official, told Les Echos newspaper last week that the river was already clean enough to swim in on some days in the year.
(Writing by Matthias Blamont; Editing by Andrew Callus and Mark Potter)
