Avignon prosecutors have already charged the 28-year-old assailant with "murder, attempted murder and possession of drugs."
"The Islamophobic aspect will be investigated when we interview this boy who claims to have heard voices," a spokesman said.
National Observatory Against Islamophobia head Abdallah Zekri, for his part, condemned the assault "as a horrible Islamophobic attack," which came just a week after France was stunned by the Charlie Hebdo killings.
Meanwhile, French Justice Minister Christiane Taubira has said that the government is considering tightening laws against racism and anti-Semitism.
Additionally, the government is seeking to give the authorities powers to block Internet hate sites "as already happens with ones that carry child pornography," Taubira said.
The past seven days have seen at least 50 anti-Muslim incidents including attacks on mosques in France, according to the country’s Central Council of Muslims.