In the French capital, around 40,000 people rallied according to the hardlineCGT union.
Mayor Anne Hidalgo said a camp to house 400 men would be opened at a site in the north of the city in mid-October.
Emergency services said one person was critically injured and airlifted to hospital.
Industrial production in France fell unexpectedly in June due to the suspension of production at some refineries.
At least 40 people were injured in the South of France as a result of the panic caused by the explosions of firecrackers.
36 year old Hamdi is the suspect in detainment.
French police have identified the second terrorist who attacked the church in Normandy as 19-year-old Abdel Malik Petitjean.
Francois Hollande has called on reservists to boost security in the wake of the attack in Nice.