A woman shows a poster Justice for Nahel during a march for 17-year-old Nahel, Thursday, June 29, 2023 in Nanterre, outside Paris. AP
The initiative on GoFundMe.com, launched by far-right media commentator Jean Messiha, received pledges of more than 1.6 million euros ($1.7 million) before it was closed in early July.
The mother of the 17-year-old shot dead in Nanterre on June 27 filed a legal complaint via her lawyer, alleging fraud, misuse of personal data and conspiracy in these crimes by Messiha.
A legal probe by specialised financial crime investigators was underway, the Paris prosecutor told AFP on Wednesday.
"We welcome the speed of the decision by the prosecutor," Yassine Bouzrou, who is acting for the dead boy's mother, told AFP.
Messiha was contacted for comment.
The 38-year-old motorbike traffic officer behind the killing of French-Algerian teenager Nahel Merzouk has been detained and charged with voluntary manslaughter.
The shooting, at point-blank range, sparked the most intense urban violence in France since 2005 and rekindled complaints about heavy-handed policing and racism in deprived areas of the country.
Messiha said the fund, which was intended for the officer's family, was "a cry from French people to demand order, a cry of love for their security forces."