With pollution a major issue for Paris and the city's public transport bursting at the seams, one start-up has a solution involving the River Seine.
The Bubble, a "flying taxi", is powered by electricity and lifts out of the water on "wings" – and boasts green credentials such as being noise and pollution-free. It costs around €200,000 to build and can reach speeds of up to 18 knots (20.7mph). Test voyages in Paris are limited to a maximum speed of 18.6mph.
The service could launch as early as spring next year, according to a press release from the Paris mayor's office. The Seabubbles start-up launched a four-day test run on the Seine on Monday.
However, the company says its journey has not all been plain sailing. During a preview on Monday morning before the official tests launched, Paris river police ordered the Bubble to stop its activity.
Co-founder Alain Thebault said regulatory issues from the City of Paris have stymied progress, leading the company to pursue projects in Switzerland and the US rather than solely in France.
"We are waiting for the authorisation to have a commercial line between east and west…but have a look, there is absolutely nobody on the river," he said, adding that France is becoming "like a museum" where tech innovation is too highly regulated.
Paris has one of the densest urban transport networks in the world, with more than 650 trains running simultaneously at rush hour and 4.7 billion trips made by public transport in the Paris region in 2016, according to figures from Paris transport network Île-de-France Mobilités.
Last Friday Parisians faced travel chaos as a strike against pension reform by all unions of the Paris transport network (RATP) crippled movement around the city, with ten of its 16 metro lines closed.
To combat pollution, Paris tightened regulations in July, banning cars with diesel engines registered between 2001 and 2005 and trucks from 2006 to 2009 within the A86 ring-road area.
The city council plans to continually tighten regulations until 2030, when only electric or hydrogen-fueled cars will be allowed on Greater Paris roads.