Two people were arrested after police found products that can be used to make explosives in a flat south of Paris on Wednesday, French Interior Minister Gerard Collomb said.
Some of the products found in the flat in Villejuif could be used to make the unstable explosive TATP, one source close to the investigation said.
TATP has been used by militants in several attacks in western Europe in recent years, including Manchester in May, Brussels in 2016 and Paris in 2015.
Gas bottles were also found in the flat, other sources said.
The police raid followed a tip from a craftsman, Collomb said in a statement. One source said it was a locksmith who saw chemical products and tools when looking into the flat.
The two people arrested were driving a small van that belongs to the flat’s tenant, a police source said.
France’s counter-terrorism prosecutor is in charge of the investigation, a judicial source said.