(JTA) — Mehdi Nemmouche, the Frenchman suspected of killing four people at the Jewish museum in Brussels, has appealed a French court-ordered extradition.

The court in Versailles late last week approved Nemmouche’s extradition to Belgium to face murder charges.

Nemmouche has been in police custody on suspicion of murder, attempted murder and possession of weapons since his arrest on May 30 in the southern French city of Marseille.

Following the court decision, Nemmouche filed an appeal, Nemmouche’s lawyer, Apolin Pepiezep, told Reuters on Sunday. The court has 40 days to rule on the appeal.

Nemmouche had refused extradition, then changed his mind on condition that he not be ordered sent to a third country, namely Israel, for trial. Two of the people murdered in the attack were Israeli.

He reportedly appealed the extradition order because Belgium has not given assurances that it would not extradite him to a third country.

French police said June 1 that they believed Nemmouche committed the May 24 murders at the Jewish Museum of Belgium and then traveled to Marseille on a bus. He was arrested at a routine customs inspection of the passengers on the bus, which left from Amsterdam via Brussels to France.

Nemmouche, who lived in the French city of Roubaix on the border with Belgium, had spent several years in a French jail for armed robbery. French authorities believe he left for Syria via Belgium to fight with jihadists in 2012 before returning to Europe.