Around 2.2 million people living within 20km (12.4 miles) of a nuclear plant will be given the tablets to protect their bodies from the effects of radiation in the event of an accident.
In 2016, five years after the nuclear accident in the Japanese city of Fukushima, France gave iodine to those living within 10km (6.2 miles) of a nuclear plant.
But only half of those eligible collected their iodine, according to report in French daily Les Echos.
Nuclear accidents usually release radioactive iodine into the atmosphere which is absorbed by a human’s thyroid gland.
It can lead to cancer years later.
Using stable iodine prevents the thyroid from absorbing radioactive iodine.
Nuclear safety authority ASN said those eligible would be sent letters instructing them to pick up their free tablets from pharmacies.
If there is a nuclear accident, they should also seek shelter, monitor the situation, limit phone communication and prepare for possible evacuation, the organisation added.
Three-quarters of France’s electricity is produced in its 58 nuclear reactors at 19 state-owned plants, making it more reliant on nuclear power than any other country in the world.
In 2014, its oldest plant in Fessenheim near the borders with Germany and Switzerland, was flooded, forcing an emergency reactor shutdown.
Fessenheim has been in use since 1977 and anti-nuclear activists have called for it to be closed permanently.
In August, it was reported that Germany was increasing its stockpile of iodine tablets in case of a nuclear accident.
After the Fukushima disaster, Germany extended the radius for those eligible for free tablets from 20km to 100km (62 miles).
Germany plans to phase out its nuclear plants by 2022 but many countries on its borders continue to operate them.