(BANG) -Marion Cotillard doesn't know if it is ''worth'' dedicating her time to charity work.

The 36-year-old actress - who is well known for working with organizations such as Greenpeace - is unsure if being a celebrity actually helps the organizations because she cannot dedicate the time necessary to them.

She said: ''I've thought a lot about whether it really changes something if I speak for a cause or an organization. Does it help? Is it worth it? Wangari Maathai, Aung San Suu Kyi, Mandela - they change things. But actors and celebrities? I don't know.

''Maybe it's because I don't give enough time to people I support. Sometimes I feel like I should choose between being an actress and having the life I have and supporting a cause that needs all the time we have.''

Marion - who was born in Paris to actor parents - admits she has often struggled in her life to deal with her own anxieties, but in recent years has made the necessary moves to be more accepting of herself.

She told Britain's Marie Claire magazine: ''I had my own world and wasn't very happy. I was not a very sociable kid. That was my personality. I was very sensitive.

''I've finally made peace with myself. I've met amazing people who gave me the keys to make peace with myself.''