FRENCH judicial authorities are investigating five people after uncovering an ultra-right plot to attack a religious venue.

A judicial official said on Tuesday that two people, one a minor, were arrested and placed under investigation in May for criminal terrorist association.

Three others were arrested in the probe that was opened in September in Grenoble, south-east France.

The anti-terrorism prosecutor's office took over the case.

The official said only one of the four was being held.

He was confirming portions of a BFMTV report saying that targets were Muslim or Jewish.

There was no link with a 2017 ultra-right plot against mosques and migrants.