Paris’ bold revival: could the 2024 Olympics restore the Seine to its former glory?

As the 2024 Olympic Games in Paris have just concluded, the attention is still focused on the river Seine and the ambitious restoration project initiated by public authorities in the run-up to the mega event. Once a vital source of recreation and social interaction for the city's residents, the Seine has been undergoing a significant restoration effort to reconnect Paris with its historic waterway and offer a new chapter in urban life. Will this ambitious initiative succeed in bringing the Seine back to life, or will the challenges of modern urbanization prove too great?

Alessia Zannoni & Rebecca De Romanis

The majority of cities around the world have been constructed near waterways or along the coast of an ocean, sea, or lake. The interconnection between urban planning and water has played a pivotal role in shaping the growth and evolution of metropolitan areas, cities, towns, rural regions, and even neighborhoods across history, and will continue to do so.

Many of Europe's most popular tourist destinations have been shaped by their rivers, with Paris serving as a prime example, as the city's identity is inextricably linked to the river Seine. Lately, it captured global attention again in connection with the Paris 2024 Olympics held between July 26 and August 11.

The Olympic Games offer cities and countries a valuable opportunity to develop and enhance various sectors, including tourism and business. For Paris, hosting the 2024 Olympic Games marks the city’s third time participating, and this time, the project has been more ambitious than ever, and embedded into a broader urban improvement initiative focusing on the city- and mainly on the Seine- that extends far beyond the scope of the Games themselves.

The Seine indeed played an important role in the 2024 Olympic Games, serving as the venue for the opening ceremony and swimming events. To achieve this, an ambitious 1.4 billion euros project was initiated with the aim of enhancing the city's sewage system and stormwater treatment facilities, and allowing athletes to swim in the river for several events.

However, the objective of this project, which commenced in 2015, was not merely to host a successful event. Rather, it sought to recreate the idyllic Paris of the 17th century, when bathing was a fashionable practice, and to provide the public with access to swimming in the Seine by creating local beaches and bathing areas along the river, taking the examples of other European cities like Bern, Munich, Zurich, Vienna, and many others, where bathing in the river is an important activity for citizens, as a blueprint. 

It might be hard to imagine now, but swimming in the Seine was actually a deeply rooted Parisian tradition. The Seine, long celebrated as a symbol of wealth and prosperity since the days of the Roman Empire, became a popular spot for bathing as early as the 17th century.

During the hot summer months, Parisians rushed to its cool waters, often taking a dip in a fully unclothed state—until public decency laws put an end to nude bathing by the end of the century.

Despite these new regulations, the Seine remained a popular destination for recreation. Floating boats equipped with hot or cold water became a common sight, allowing bathers to enjoy the river's refreshing in a more private setting. Eventually, these boats evolved into bathhouses, solidifying the Seine's reputation as a special retreat in the heart of the city.

Even with the advent of swimming pools, the Seine remained a favored spot for those seeking a more natural experience, and its important role was highlighted on June 22, 1913, when the French diving championships were held in the Seine. 

But why is swimming in the Seine no longer an option? As the 20th century progressed, the growing industrialization and urban expansion of Paris started to have a negative impact on the river's water quality: urbanization meant the discharge of domestic sewage into surface water. By 1923, concerns over pollution had reached a critical point, leading authorities to ban bathing in the Seine. 

For cities with a long history like Paris, cleaning the Seine presents a significant challenge, mainly due to its combined sewage system. This system routes both the city’s wastewater and stormwater through the same pipe. It means that when heavy rain falls, these pipes can become overwhelmed, leading to untreated wastewater flowing directly into the river.

The situation has worsened in recent years due to the climate crisis, which has brought unusually heavy and unpredictable rainfall to Northern Europe. The increased rainfall puts further pressure on the city's sewage infrastructure, resulting in more frequent and severe pollution of the Seine. In addition to that, there is questionable behavior concerning the discharges upstream of the city, where areas less served by the sewer system often are the theater of discharges to surface water.

The presence of untreated sewage in the river introduces harmful viruses and bacteria, such as Escherichia coli, which naturally resides in the intestines of humans and animals. Escherichia coli can cause diarrhea, stomach pain, and nausea in humans. This contamination not only makes the river unsafe for swimming but also interferes with the delicate ecosystem, threatening the wildlife that depends on the Seine.

The aim of the Parisian river clean-up project was split into two parts: the hosting of the long-distance (10 km) swimming races as well as the triathlon and para-triathlon competitions during the 2024 Olympics; and the opening of public baths for citizens and tourists starting next year. The aim of depolluting the Seine would result in opening three natural pools in the Summer of 2025 for citizens and tourists, with lifeguards, showers, changing rooms, etc.  

Therefore, it was not only a plan limited to the Olympics period.  It went beyond that, becoming an urbanistic strategy in accordance with the political line of the Parisian mayor Anne Hidalgo. Her administration works for a greener and eco-friendlier Paris, and has already achieved significant reductions in air pollution. In fact, making the Seine suitable for bathing would mean making the city more bearable for citizens during the summer heat, but also restoring the Seine’s ecosystem. 

The 1,4 billion plan to depollute the Seine has been focusing on cleaning up the wastewater in the river before it enters the city, and eliminating buildings’ discharge flowing into the river. The activities were divided into two parts: the construction of a storage pool for sewage and the elimination of bacteria to clean up the Seine water. In addition to that, some work has been done to reduce the visible pollution, such as the waste that some citizens and tourists drop in the river. The biggest part of the strategy was the construction of the Austerlitz basin in the 13th arrondissement. After more than three years of construction, it became operational in the Spring of 2024. It has a volume of 46.000 m3, is 30 meters tall, and has a diameter of 50 meters - around 90 million euros were spent for its construction. The basin is used to retain the water excess in the sewer system, avoiding irregular flows caused by strong precipitations and rains. It was able to successfully lower the bacterial count, making the Seine more suitable for bathing.

On 17th July, Paris mayor Anne Hidalgo bathed in the river to prove to the skeptical citizens that it was possible. However, due to precipitation at the end of July, bacteria levels rose, rendering the river unsuitable for training. Athletes were informed that they could swim in the river only a few hours before the actual competitions.

After swimming in the river, numerous triathletes and open-water swimmers (such as the 800m gold medal winner Daniel Wiffen) suffered from gastro-intestinal contaminations and were hospitalized. Besides that, due to the frequent rainfall during the Olympics, some athletes were not able to train and test the river before competing. Therefore, the effectiveness of the Seine’s clean up project remains questionable - according to the recent events at least, it cannot be said that the cleaning-up of the river for the Olympics 2024 has been achieved in time.

However, the project is not condemned in its entirety. The water is indeed clearer and, with new investments and the construction of new sewage systems that could replace the very old ones, the river could actually become more attractive and more sustainable for the Parisian environment: the project has already had a positive impact on local wildlife, with more than 30 fish species now living in the Seine. 

The work is not to be considered finished, the rain influence is still too relevant for the eco-friendliness of the project and for how it impacts the levels of bacteria in the river. As we mentioned, the building of new sewers are essential for continuing to work long-term on this project, making it effectively innovative for the city of Paris. 

Nevertheless, the Olympics have given an interesting input to rethink the relationship between the city of Paris,  its citizens, and the Seine. In fact, even if we cannot say that the work on the Seine was successful for the Olympics 2024, it could have a positive impact if the strategy does not stop here. A clean river would indeed represent an environmental and urban innovation for the City of Lights, but it could also be taken as an example for different European (and not only European) cities: the legacy of the project being that it is possible  to significantly enhance the life quality of a metropolis by depolluting a river.