

Because he’s a creep
Besson’s second wife was actress and director Maïwenn Le Besco, whom he started dating when he was 32 and she was 15 after having met 3 years earlier.[43] They married in late 1992 when Le Besco, 16, was pregnant with their daughter Shanna
Le Besco later claimed that their relationship inspired Besson’s film Léon (1994), where the plot involved the emotional relationship between an adult man and a 12-year-old girl (played by then 12-year-old Natalie Portman).[43] Their marriage ended in 1997, when Besson became involved with actress Milla Jovovich, then 19, during the production of The Fifth Element
Edit: And the multiple rape and sexual harrasment claims
Yes, The Fifth Element and La Femme Nikita are outstanding films, Leon is worth watching for Gary Oldman but the lolita stuff was completely unnecessary.