The campaign groups want the court to hold the state responsible for ecological damage and say victory would mark a symbolic step in the fight to persuade governments to do more.
An international accord signed in Paris five years ago aims to limit global warming to less than 2 degrees Celsius over pre-industrial levels, and preferably to 1.5 degrees.
But experts say governments are far from meeting their commitments and anger is growing among the younger generation over inaction, symbolised by the campaigns of Swedish teenager Greta Thunberg.
The French case is part of a mounting push from climate campaigners across the world to use courts against governments.
In 2019, the Dutch Supreme Court ordered the Netherlands to slash its greenhouse gas emissions by at least 25 percent of 1990 levels by the end of 2020 after a case brought by an NGO.
The French case began in December 2018 when four NGOs accused the government of failing to reduce emissions in a formal complaint backed by more than two million people in an online petition – a French record.
Unsatisfied with the response, the NGOs, including Greenpeace France and Oxfam France, then filed their legal complaint in March 2019 seeking symbolic damages of just €1 ($1.21) from the state.
Exceeding carbon budgets
“We are full of hope for this hearing and the decision that will follow,” Jean-Francois Julliard, director of Greenpeace France, told AFP.
Julliard said he wanted the court to recognise that the state was not doing enough.
“The icing on the cake would be a decision to urge the state to do more to put France back on the trajectory of the Paris Agreement”, he said.
While France has committed to reducing its emissions by 40 percent by 2030 compared with 1990, the NGOs say it is exceeding the carbon budgets it pledged.
They also complain of shortcomings in the energy renovation of buildings or development of renewable energy, saying this is having a daily impact on the health and quality of life in France.
Natural disasters 'increasing'
The NGOs have presented 100 testimonies from individuals with their case, after collecting more than 25,000 online.
“For me, climate change – with the increase in the frequency of natural disasters, the rise in sea temperatures and the progression of coastal erosion – is a reality now,” said Jean-Francois, a producer of mussels on the island of Oleron in western France.
The government rejects accusations of inaction, pointing to the energy-climate law of 2019 that “reinforces the climate goals” by aiming for carbon neutrality by 2050 or a 40 percent drop in the use of fossil fuels by 2030.
In its defence sent to the court, the government also rejected the request for compensation over ecological damage, arguing that the French state cannot be held solely responsible for climate change when France represents around 1 percent of global emissions.
Julliard acknowledged the case could be a double-edged sword for the NGOs.
“If we lose, then it will be easy for the state to say: 'We won in court, so stop your incessant demands,'” he said.