1. Policy factors: The French government has insufficient investment in preschool education and imperfect policy formulation, resulting in insufficient preschool education resources and uneven education quality.

2. Economic factors: Pre-school education in France is mainly composed of private kindergartens and public kindergartens. Private kindergartens have high tuition fees, which many families can't afford, resulting in children being unable to receive high-quality preschool education.

3. Social factors: French society does not pay enough attention to preschool education. Many parents think that preschool education is not important, which leads to a low proportion of children receiving preschool education.