Four relatives of a man killed after ramming his car into a police convoy in Paris's Champs-Elysees are in custody.
The Paris prosecutor's office said today that the four family members were detained overnight in the anti-terrorism investigation into yesterday's attack.
Officials said the man was on police radar for ties to radicalism.
French Prime Minister Edouard Philippe confirmed on BFM television yesterday that the man had a gun permit but that it was initially issued before the attacker was flagged to authorities.
The man set off a fiery blast when he drove his car packed with arms and explosives into police in one of Paris's busiest shopping districts.
No-one else was hurt in the incident.
The Champs-Elysees reopened overnight.