Barcelona terrorists visited Eiffel Tower and stayed near apartment containing explosives in Villejuif

In an interview with the radio station France Info, Collomb says it is 'known' that the killers were in the French capital just days before the attacks, that they bought a camera in the FNAC store and that they visited the city's most famous landmark.

Their itinerary has been traced in full thanks to their mobile phones, which have been confiscated by Spanish authorities.

Collomb said the fact they were in France just before August 17 was discovered thanks to a motorway toll booth employee who reported that an Audi of the same registration number as the one used in the Cambrils attack had been through the pay gates.

The 'impromptu' trip to Paris, which was over August 11 and 12, appears to have some significance, authorities believe – French prosecutor François Molins says 'nobody can believe' they travelled to the city 'just to buy a camera from the FNAC'.

Three of the terror cell were in Paris, staying at a hotel in the suburb of Malakoff in the south of the city close to Villejuif where, on Wednesday last week, a explosives laboratory was found in an apartment.

The laboratory and explosives were the same type as found in the house in Alcanar (Tarragona province) which blew up just before the Barcelona and Cambrils attacks.

Three people were arrested in connection with the Villejuif findings.

Investigations are now under way to see whether the Catalunya terrorists had been in contact with other Jihad warriors in Paris, perhaps to obain material or to find out how to make incendiary devices.

It is believed there may be some connection between the laboratory in Villejuif and the conflagration in Alcanar.

The photograph shows one of the Catalunya terrorists, Mohammed Houli Chemlal, who was injured in the Alcanar blast.