Marion Cotillard joined thousands of Parisians marching for climate action on Sunday.
The French actress, 45, kept a low profile with a baseball cap and face mask as she joined crowds walking in protest ahead of a lawmakers reviewing bill on climate change.
Marching from the Place de l'Opéra to Place de la République, the A-lister held a placard that read: 'Marquons l'histoire nen soyons pas la honte,' which translates to: 'Let's make history, let's not be ashamed.'
French lawmakers are set to start examining the Climate and Resilience bill on Monday, which aims to reduce carbon emissions in the country by 40 percent by 2030.
However, the bill has been criticised for not limiting France's carbon emissions enough, prompting protests.
As well as joining the protest, Marion used her massive Instagram following to recruit more activists.
She told her 1.5 million followers they should consider taking to the streets to 'show that the climate movement is back' adding their presence on the streets would show government officials: 'We are watching them'.
Marion is a well-known environmental campaigner, and last year ventured to Antarctica with Greenpeace to learn about the devastating effect climate change, plastic waste and industrial fishing has on wildlife.
Speaking to the BBC from Antarctica at the time, the Inception star said: 'This is honestly the most beautiful place I've ever been in my life.
'They're mapping out how humans are impacting whales, penguins and other animals here. And as pristine as it looks, even a remote place like this one is impacted by harmful human activities.
'Scientist found microplastics, microfibres, and this is going everywhere.'
Marion also addressed the film industry's impact on the environment, saying: 'Any industry has an impact on the environment. Flying, which is obviously a big thing in this job.
'We're not perfect, but if you're aware you're not perfect, and you try to do your best, then it's a first step to awareness and change.'
As well as acting, Marion also models, and was recently announced as the new face of Chanel No. 5 perfume.
