Bernard Cazeneuve said on Tuesday that two men, aged 20 and 24, were arrested on 19 December and were being held for questioning.
Both are thought to have had contact with another Frenchman, currently believed to be in Syria.
France saw its worst attacks in decades last month, with 130 killed in Paris.
Speaking in the southern city of Toulouse, Mr Cazeneuve said 10 attacks had been foiled so far this year in France.
He said the investigation into the latest alleged plot south-west of Paris will look into whether the Frenchman in Syria, thought to be a jihadist, ordered the attack.
One of the detainees confessed they had intended to attack police officers, military personnel and anyone identified with the French state, Mr Cazeneuve said.
Investigators think the suspects had raised money for the plot and were searching for weapons.
One of the men arrested is reported to be of Moroccan descent, while the other is said to be from Togo.
One suspect was reportedly unknown to police, while the other was a known petty criminal.