Vaincre l'Autisme (Defeating Autism), the organisation behind the eleventh "March for Hope", says France has fallen so far behind in autism treatment that people often needlessly end up in psychiatric institutions.
Autism can emerge due to many factors in early childhood and persist into adulthood, and is characterised by difficulties communicating and interacting socially.
The organisation, which says nearly one in 100 children is autistic, is calling for policies that focus on early diagnosis, more appropriate treatments and adapted education to better integrate autistic children in society.
While many countries pursue behavioural and other therapies to help them develop skills needed to function in society, France has long embraced an approach more fixated on Freud and psychoanalysis.
Amélie Churlet of Vanquish Autism says psychoanalysis still has a strong grip in France to this day.
Consequently, people with autism in France face a different set of challenges from other neighbouring European countries, she added.
"[The World Health Organisation] WHO has said that autism is a neurobiological problem, which is really different from what a lot of people still think in France," said Churlet. "So if that doesn’t change, the situation won't change."
France's approach to autism has enraged critics and families who say that children suffering from autism could have been treated earlier, and more successfully with early screening and diagnosis.
Earlier this month, an outraged mother spent a day protesting atop a crane in the southern French city of Toulouse condemning the reported removal of her 8-year-old autistic son from school.
This issue has also been addressed by the Council of Europe, which last month for the second time condemned France for failing to put 80 per cent of autistic children in school.
France's Health Ministry has unveiled three plans for autism treatment and training, the first launched in 2005 and the latest in 2013 - but the Council of Europe has said these plans do not go far enough.
"Every step they have to fight for their rights and many, many children and adults end up in psychiatry hospitals with medicine and it’s not what they should get," said Churlet. "They should get behavioural analysis, get educational treatments so they can really live in the society and have the right of every citizen."