From CNN:

Three women who were likely planning an “imminent and violent” attack were arrested near Paris on Thursday, French Interior Minister Bernard Cazeneuve said.

According to Cazaneuve, the women, whom he referred to as radicalized, were arrested in connection with gas cylinders found this week inside a car left in front of Notre Dame cathedral in Paris.
One police officer was injured in the shoulder when one woman attacked him with a knife in Boussy-Saint-Antoine, southeast of Paris, the minister told reporters. The injury was not life-threatening.

“I would like to express my gratitude to him and to his colleagues who had to open fire when faced with individuals armed with knives,” Cazaneuve said.
One of the women also was hurt.

The minister said the unidentified women are 19, 23 and 39 years old.
France has been under a state of emergency since the Paris terror attacks in November last year, and authorities have struggled to monitor thousands of domestic radicals on their radar.

An earlier report from The Daily Mail indicated the women may have been doing a “test run” for an attack when they were arrested.

Women allegedly planning ‘imminent and violent attack’ arrested near Paris