Paris police headquarters says experts successfully rendered the 880-pound (400-kilogram) bomb harmless in a few hours.
The operation Saturday forced the closure of two neighborhoods in Boulogne-Billancourt, southwest of Paris. Residents were accommodated in special centers or told to go to the movies.
The bomb was discovered Jan. 27 on an old factory site of Renault automobiles under renovation.
Such evacuations are not uncommon in France, but are mainly in Normandy where bombs rained down after the Allied D-Day invasion.