Paris has been on high alert after the multiple bombings and shootings in November that killed 130 people (Photo: BBC)

The four are said to have links with radical Islam. One is thought to have been plotting “violent acts” in Paris. They had been under surveillance by French intelligence on suspicion of a "possible plan to attack" but the threat has not been confirmed, said a police source. The raids turned up no weapons, but computer hardware and data were seized for analysis.

The arrests came just one day after a police raid in a Brussels’ suburb on Tuesday. France remains in a state of emergency against terrorist attacks.