A man has been placed in custody for alleged links to a gunman who killed a policeman on Paris's famed Champs-Elysees just days before the first round of France's presidential election, a judicial source said on Tuesday.
The 23-year-old was arrested on Monday in the Paris region, the source said. Investigators are trying to find out where the gunman, 39-year-old Karim Cheurfi, got the Kalashnikov he used in the April 20 attack.
A note praising the Islamic State was found next to the body of Cheurfi, who shot dead an officer and wounded two other policemen and a German passerby before being killed in a firefight.
Police later found other weapons in Cheurfi's car including a shotgun and knives.
The Islamic State group claimed the shooting as the work of one of its "fighters". It was the latest in a string of attacks that have claimed 239 lives around France since 2015.
However, the IS named the shooter as Abu Yussef the Belgian, which does not correspond to Cheurfi, who was from the eastern Parisian suburbs.