France's capital Paris reopened the Seine River to swimmers on Saturday for the first time in over a century.

AFP news agency said dozens of swimmers were present for the opening at 8:00 a.m. (0600 UTC/GMT), diving into the water under the watchful eye of lifeguards.

The move is part of the legacy of the Paris 2024 Olympics and comes amid sweltering temperatures across Europe, including France's second-warmest June since records began.

Where will Parisians be allowed to swim?

Paris authorities have created three outdoor pool zones, complete with changing rooms and showers and supervised by lifeguards.

The pools are located opposite L'île aux Cygnes (Swan Island) near the Eiffel Tower, close to Notre-Dame Cathedral and opposite the Bibliotheque national de France.

The swimming zones also have beach-style furniture, offering space for 150 to 300 people to sunbathe.

Access to the pools will be free of charge until August 31st.

A statement from the city government said water quality will be continuously monitored.

Authorities said lifeguards would assess visitors' swimming abilities, particularly due to strong currents, an average depth of 3.5 meters (11 feet) and boat traffic.

Why was swimming in the Seine banned?

Bathing in the Seine was officially banned in 1923, primarily due to health risks from pollution.

The river has historically been contaminated with high levels of bacteria, such as E. coli and enterococci, from sewage overflows, industrial discharge, and urban runoff.

These pollutants pose significant risks of illness for swimmers, including skin infections and gastrointestinal issues.

Additionally, strong currents, boat traffic, and debris in the river create hazardous conditions for bathers.

Despite being illegal, swimming was still practised until the early 1960s and there have been several attempts to remove the ban.

In 1988, then-Paris mayor and future president Jacques Chirac first advocated for its reversal.

Why lift the ban on bathing?

Authorities promised ahead of the Paris 2024 Olympics that the water in the Seine would be cleaned up to allow athletes to compete in its waters.

Around €1.4 billion ($1.6 billion) was spent on improving water quality, which officials promised would benefit not just the Olympic athletes but residents and tourists for years to come.

A massive underground storage tank was created to hold wastewater and prevent untreated sewage from entering the river during heavy rain. Wastewater treatment plants were also upgraded.

During the games, the river hosted the triathlon swimming legs and open water swimming events. However, the swims weren't without controversy, as some athletes fell sick afterward.

Paris Mayor Anne Hidalgo has said that cleaning up the Seine for the Olympics was part of a broader effort to adapt the city to climate change and enhance quality of life.

"Everyone should be able to swim in the Seine starting this summer," said French Sports Minister Marie Barsacq when the move was announced in May.

Ahead of Saturday's launch, French President Emmanuel Macron praised the work undertaken to open the swimming zones, writing on X that it was a "source of pride for the country."

Edited by: Kieran Burke