The fire erupted early on Thursday at a storage facility near the city of Rouen.
No injuries were reported in the blaze, which sent acrid black smoke billowing over some 22 kilometres.
"The fire is out," a spokesman for the regional fire service announced on Friday morning, adding that emergency staff would remain at the site to monitor undamaged storage tanks.
The spokesman said some white smoke was still coming from the factory and there was an "unpleasant smell".
More than 200 firefighters were deployed to tackle the blaze at the plant, just a few kilometres from the centre of Rouen, a city with a population of 100,000 people.
Lubrizol said the fire damaged a storage facility, a drumming warehouse and an administrative building, and that the cause was still unknown.
The company has advised residents not to eat fruit or vegetables from local gardens without washing them thoroughly, and not to touch the soot or other particles on the ground.
Floating anti-pollution barriers have been placed on the River Seine due to the risk that fuel or waste water from the site could overflow retention ponds.
Prosecutors have opened an inquiry to establish the cause of the blaze.