Another couple has been detained south of Paris in an investigation into seven gas cylinders found in an abandoned car next to Notre Dame Cathedral.
The Paris prosecutor's office said today that police detained the man and woman in the Loiret region.
Another couple, suspected of links to radical Islam, was detained in a highway rest area near the southern city of Orange on Tuesday in the same case. It is unclear if the couples had any link to each other.
Prosecutors opened a criminal terrorist investigation after the discovery of the car, which had gas canisters and papers with Arabic writing inside.
The car's owner went to police to report that his "radicalised" daughter was missing.
He was briefly detained and then released. His daughter still is being sought.